European Journal of Pharmacology (v.654, #3)
Editorial Board (ii).
Effect of strontium on human Runx2 +/− osteoblasts from a patient with cleidocranial dysplasia by Piero Römer; Michael Behr; Peter Proff; Andreas Faltermeier; Claudia Reicheneder (195-199).
Strontium represents a new generation of anti-osteoporotic agents that exert anti-catabolic and anabolic effects on bone cells at once. We used strontium in vitro in order to examine its potential to stimulate bone marker transcription and hydroxyapatite formation on isolated Runx2 +/− osteoblasts from a patient with cleidocranial dysplasia. This disease is evoked by heterozygous mutations of Runx2, an important transcription factor for osteoblast maturing and transcription of osteogenic genes, which results in insufficient gene dosage of Runx2. This genetic defect is responsible, for example, for patent fontanels, sometimes throughout the life, supernumerary teeth, and aplasia or hypoplasia of clavicles and mimics symptoms of hypophosphatasia. In this trial, we investigated the effect of strontium on gene expression of bone marker proteins, the formation of hydroxyapatite and the cell proliferation of strontium-treated Runx2 +/−-osteoblasts. Unlike normal osteoblasts, gene expression of bone marker proteins was not affected in strontium-treated Runx2 +/− osteoblasts, while improved hydroxyapatite formation was noted in the extracellular matrix. A WST-1 cell proliferation assay with strontium-treated Runx2 +/−-osteoblasts showed that strontium induces cell proliferation and growth. This effect might be responsible for the improved mineralisation of the extracellular matrix of strontium-treated Runx2 +/−-osteoblasts observed.
Keywords: Strontium; Cleidocranial dysplasia; Runx2; Osteoblast; Hydroxyapatite;
Receptor-specific functional efficacies of alkyl imidazoles as dual histamine H3/H4 receptor ligands by Tim Kottke; Kerstin Sander; Lilia Weizel; Erich H. Schneider; Roland Seifert; Holger Stark (200-208).
Histamine H3 and H4 receptors are highly related G protein-coupled receptors. Preclinical and clinical data strongly suggest the potential therapeutic application of selectively acting histamine H4 receptor ligands to inflammatory conditions but also hint at a certain interference of the two receptors in diseases attended with itch and pain. The aim of this investigation was to identify dual acting ligands as pharmacological tools. Receptor binding profiles of ω-(1H-imidazol-4-yl)alkyl derivatives structurally defined as amides, carbamates, esters, ethers, ketones and ureas were evaluated with respect to their potencies at histamine H3 and H4 receptors. A two-step screening method based on in vitro radioligand binding studies and functional [35S]GTPγS binding experiments was performed. The examined series of imidazole-containing compounds displayed both, selective histamine H4 receptor and dual acting histamine H3/H4 receptor ligands. Slight structural modifications caused major differences in selectivity profiles and on functional properties at the human histamine H4 receptor. N-(3-(1H-Imidazol-4-yl)propyl)-2-cyclohexylacetamide 11 was identified as most potent and selective human histamine H4 receptor ligand in this series (K i = 45 nM). Amide- and ether-containing structures consistently exhibited partial agonist efficacies, whereas ureas, ketones, esters and carbamates mainly acted as antagonists and inverse agonists. We identified novel dual acting histamine H3/H4 receptor ligands with varying efficacies at the histamine H4 receptor subtype, whereas histamine H3 receptor antagonism was kept constant, e.g. 3-(1H-imidazol-4-yl)propyl (cyclohexylmethyl)carbamate 19 or 4-(3-(3-phenylpropylthio)propyl)-1H-imidazole 30. These compounds state valuable pharmacological tools in studies of diseases, in which histamine H3 and H4 receptor signalling contributes to pathophysiological conditions.Display Omitted
Keywords: Histamine receptor; Inflammation; Agonist; Inverse agonist; GTPγS binding; Imidazole;
Apoptosis induced by a new flavonoid in human hepatoma HepG2 cells involves reactive oxygen species-mediated mitochondrial dysfunction and MAPK activation by Huibin Liu; Yuling Xiao; Chaomei Xiong; Anhua Wei; Jinlan Ruan (209-216).
Earlier reports suggest that protoapigenone showed remarkable anticancer activities. In the present study, the cytotoxic effect of a new flavonoid, 2-(cis-1, 2-dihydroxy 4-oxo-cyclohex-5-enyl)-5, 7-dihydroxy-chromone (DEDC), which is a protoapigenone analog, was investigated in human hepatoma HepG2 cells. We found that hepatoma cells were highly susceptible to DEDC in contrast with normal cells. The sustainable and rapid generation of reactive oxygen species was observed in DEDC-induced cell death. Following oxidative stress, DEDC sequentially decreased mitochondrial membrane potential (ΔΨm), reduced Bcl-2 expression, increased cytochrome c release, and activated caspase-3, -8, and -9. Phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen activated protein kinase (MAPK) was stimulated by treatment with DEDC. To further investigate the mechanisms of the DEDC-induced cell death, we examined the effects of reactive oxygen species scavenger N-acetyl-L-cysteine (NAC) and selective inhibitors for MAPK pathways on the cell death. The DEDC-induced cell death was significantly inhibited by both NAC and JNK inhibitor SP600125, but promoted by p38 MAPK inhibitor, SB203580. Together, DEDC may have antitumor effects in HepG2 cells through reactive oxygen species production as well as activation of MAPK signaling pathways.
Keywords: Flavonoid; HepG2 cell; Reactive oxygen species; JNK; p38; Apoptosis;
Megestrol acetate inhibits the expression of cytoplasmic aromatase through nuclear C/EBPβ in reperfusion injury-induced ischemic rat hippocampus by Pelin Kelicen Ugur; Sevda Lule; Mehtap Cincioglu; Can Pekiner; Yasemin Gursoy-Ozdemir (217-225).
Global ischemia after cardiac arrest, intraoperative hypoxia/hypotension, and hemorrhagic shock causes brain injury resulting in severe neurological and neurobehavioral deficits. Neurodegeneration can be prevented by local aromatase expression, and estrogen synthesis can be neuroprotective in ischemia/reperfusion. Therefore, aromatase, the enzyme that transforms androgens to estrogens, may be a potential target for the study of reperfusion injury after brain ischemia. We investigated the expression of aromatase and C/EBPβ using western blotting in rat hippocampus after transient global ischemia plus hypotension. Immunohistochemical analysis was performed for aromatase. After 10 min of ischemia, aromatase and C/EBPβ expression in cytosolic extracts were observed after 10 min and 24 h of reperfusion. The expression of both proteins was similar in control and damaged tissues. Immunoblot analysis demonstrated that the highest aromatase expression appeared in damaged hippocampi after 1 week and was gradually reduced after 2–10 weeks. C/EBPβ expression increased at 1 week in nuclear extracts of damaged hippocampi. The aromatase inhibitor megestrol acetate (20 mg/kg/day) suppressed aromatase and nuclear C/EBPβ levels in ischemic hippocampi. Our findings indicate that ischemia as well as chronic neurodegenerative processes leads to an increase in cytoplasmic aromatase and nuclear C/EBPβ. Thus, it is possible to hypothesize an interaction between this enzyme gene and transcription factor.
Keywords: Aromatase; C/EBPβ; Megestrol acetate; Transient global ischemia; Carotid artery occlusion; (Rat);
Neuroprotective and anti-inflammatory effects of mollugin via up-regulation of heme oxygenase-1 in mouse hippocampal and microglial cells by Gil-Saeng Jeong; Dong-Sung Lee; Dong-Chun Kim; Yurngdong Jahng; Jong-Keun Son; Seung-Ho Lee; Youn-Chul Kim (226-234).
Mollugin, a bioactive phytochemical isolated from Rubia cordifolia L. (Rubiaceae), exhibits antimutagenic activity, antitumor activity, antiviral activity, and inhibitory activity in arachidonic acid- and collagen-induced platelet aggregation. In this study, we investigated the effects of mollugin as a neuroprotective agent in glutamate-induced neurotoxicity in the mouse hippocampal HT22 cell line and as an anti-inflammatory agent in lipopolysaccharide-induced microglial activation in BV2 cells. Mollugin showed potent neuroprotective effects against glutamate-induced neurotoxicity and reactive oxygen species generation in mouse hippocampal HT22 cells. In addition, the anti-inflammatory effects of mollugin were demonstrated by the suppression of pro-inflammatory mediators, including pro-inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) and cytokines (tumor necrosis factor-α and interleukin-6). Furthermore, we found that the neuroprotective and anti-inflammatory effects of mollugin were linked to the up-regulation of the expression of heme oxygenase (HO)-1 and the activity of HO in HT22 and BV2 cells. In addition, the effects of mollugin resulted in the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) in HT22 and BV2 cells. Furthermore, mollugin also activated the p38 mitogen-activated protein kinase (MAPK) pathway both in HT22 and BV2 cells. These results suggest that mollugin may be a promising candidate for the treatment of neurodegenerative diseases related to neuroinflammation.
Keywords: Mollugin; Heme oxygenase (HO)-1; Neuroprotection; Anti-inflammation; HT22; BV2;
Sustained subcutaneous infusion of nicotine enhances cholinergic vasodilation in the cerebral cortex induced by stimulation of the nucleus basalis of Meynert in rats by Sae Uchida; Harumi Hotta; Hidemi Misawa; Koichiro Kawashima (235-240).
The present study examined the effects of sustained nicotine exposure on the cholinergic vasodilative system originating in the nucleus basalis of Meynert (NBM) and projecting to the cerebral cortex in rats. Rats received sustained subcutaneous nicotine (100 μg/kg/h) for 14 days. Under urethane anesthesia, the vasodilation response and acetylcholine release in the parietal cortex induced by electrical stimulation of the NBM (10–200 μA) were measured. The basal level of acetylcholine release was significantly higher in nicotine-treated rats than in saline-treated control rats. In the control rats, both the acetylcholine release and blood flow were increased by NBM stimulation in a stimulus intensity-dependent manner, and a threshold of 50 μA. In nicotine-treated rats, the threshold intensity of NBM stimulation producing increases in acetylcholine release and blood flow was reduced to 20 μA. The stimulus intensity-dependent acetylcholine release and vasodilation by NBM stimulation were significantly larger in nicotine-treated rats than in control rats. We conclude that sustained subcutaneous infusion of nicotine enhances cholinergic vasodilative system in the cerebral cortex originating in the NBM.
Keywords: Chronic nicotine; Nucleus basalis of Meynert; Cholinergic vasodilative fibers; Cortical cerebral blood flow; Vasodilation; Acetylcholine release; (Rat);
Brain α4β2 nicotinic acetylcholine receptors are involved in the secretion of noradrenaline and adrenaline from adrenal medulla in rats by Takahiro Shimizu; Kenjiro Tanaka; Takashi Hasegawa; Kunihiko Yokotani (241-248).
Recently, we reported that intracerebroventricularly (i.c.v.) administered (±)-epibatidine (a non-selective agonist of nicotinic acetylcholine receptors) elevates plasma noradrenaline and adrenaline through brain nicotinic acetylcholine receptor-mediated mechanisms in rats. In the present study, we characterized the receptors involved in these responses using selective agonists and antagonists of nicotinic acetylcholine receptor subtypes in anesthetized rats. (±)-Epibatidine (5 and 10 nmol/animal, i.c.v.) and (−)-nicotine (250 and 500 nmol/animal, i.c.v.) both elevated plasma noradrenaline and adrenaline (adrenaline > noradrenaline) but the former was more efficient than the latter. The (±)-epibatidine (5 nmol/animal, i.c.v.)-induced elevation of plasma catecholamines was reduced by dihydro-β-erythroidine (a selective antagonist of α4β2 nicotinic acetylcholine receptors) (100 and 300 nmol/animal, i.c.v.), while methyllycaconitine (a selective antagonist of α7 nicotinic acetylcholine receptors) (100 and 300 nmol/animal, i.c.v.) had no effect on the (±)-epibatidine-induced responses. RJR-2403 (a selective agonist of α4β2 nicotinic acetylcholine receptors) (2.5 and 5 μmol/animal, i.c.v.) elevated plasma noradrenaline and adrenaline (adrenaline > noradrenaline), while PNU-282987 (a selective agonist of α7 nicotinic acetylcholine receptors) (2.5 and 5 μmol/animal, i.c.v.) had no effect. Furthermore, the RJR-2403 (5 μmol/animal, i.c.v.)-induced responses were abolished by acute bilateral adrenalectomy. Immunohistochemical procedures demonstrated the expression of α4 and β2 nicotinic acetylcholine receptor subunits on the spinally projecting hypothalamic paraventricular neurons. Taken together, brain α4β2 nicotinic acetylcholine receptors seem to be involved in the secretion of noradrenaline and adrenaline from adrenal medulla in rats.
Keywords: (±)-Epibatidine; Brain; α4β2 Nicotinic acetylcholine receptor; Noradrenaline; Adrenaline; Adrenal medulla;
Involvement of a NO–cyclic GMP–PKG signaling pathway in nitrous oxide-induced antinociception in mice by Yao Zhang; Lindsay P. Quock; Eunhee Chung; Yusuke Ohgami; Raymond M. Quock (249-253).
The antinociceptive effect of nitrous oxide (N2O) is dependent on nitric oxide (NO); however, the next step in the pathway activated by NO is undetermined. The present study was conducted to test the hypothesis that a N2O action involves sequential activation of NO synthase, soluble guanylyl cyclase and protein kinase G to induce an antinociceptive effect in mice. The antinociceptive responsiveness of male NIH Swiss mice to N2O was assessed using the acetic acid abdominal constriction test. Different groups of mice were pretreated with either saline, the NO scavenger 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3-oxide (carboxy-PTIO), the guanylyl cyclase-inhibitor 1H-[1,2,4]-oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), the protein kinase G-inhibitor Rp-isomer of 8-(4-chlorophenylthio)-guanosine-3′,5′-cyclic monophosphorothioate (Rp-8-pCPT-cGMPS) or the selective phosphodiesterase V-inhibitor 1,2-dihydro-2-[(2-methyl-4-pyridinyl)methyl]-1-oxo-8-(2-pyrimidinylmethoxy)-4-(3,4,5-trimethoxyphenyl)-2,7-naphthyridine-3-carboxylic acid methyl ester hydrochloride (T 0156). Vehicle (saline)-pretreated mice responded to N2O in a concentration-dependent manner. This antinociceptive effect was antagonized by systemic pretreatment with carboxy-PTIO and ODQ and central pretreatment with Rp-8-pCPT-cGMPS. In each case, the dose–response curve for N2O was progressively shifted to the right by increasing the dose of each pretreatment drug. On the other hand, N2O-induced antinociception was enhanced by systemic pretreatment with T 0156; the dose–response curve for N2O was shifted to the left. The ATP-sensitive potassium channel blocker glibenclamide was without influence on the antinociceptive effect of N2O. These results support the hypothesis that N2O-induced antinociception in mice is mediated by a NO–cyclic GMP–PKG pathway.Display Omitted
Keywords: Nitrous oxide; Antinociception; Nitric oxide; Cyclic GMP; Protein kinase G; (Mouse);
Increased in vivo [11C]raclopride binding to brain dopamine receptors in amphetamine-treated rats by Michael R. Kilbourn; Edward F. Domino (254-257).
The hypothesis that repeated daily doses of amphetamine increases the number of available dopamine D2 receptors in vivo in rat striatum, and may enhance the response to subsequent amphetamine challenge doses, was examined. The in vivo binding potentials of [11C]raclopride, a D2 receptor antagonist, were determined in male CD-1 rats under five conditions: (1) drug-naïve with saline challenge, (2) drug naïve with 5 mg/kg amphetamine challenge, (3) amphetamine-dosed (five daily repeated s.c. doses of 5 mg/kg amphetamine) and saline challenge, (4) amphetamine-dosed and amphetamine challenge, and (5) saline treated (five daily repeated s.c. doses) and saline challenged. Radiotracer studies in amphetamine-dosed animals were done after a 10-day drug free interval. In the amphetamine-dosed group the baseline [11C]raclopride binding was increased by 63% compared to saline-treated controls. The response to an amphetamine challenge, evidenced by a reduction of [11C]raclopride binding, was doubled in amphetamine-dosed animals (40%) compared to drug-naïve controls (20%). These results support increased baseline in vivo dopamine D2 receptor antagonist radioligand binding after repeated amphetamine administration in rats.
Keywords: Raclopride; Amphetamine; Sensitization;
Role of prostanoid IP and EP receptors in mediating vasorelaxant responses to PGI2 analogues in rat tail artery: Evidence for Gi/o modulation via EP3 receptors by Nelson N. Orie; Lucie H. Clapp (258-265).
Prostanoid IP receptors coupled to Gs are thought to be the primary target for prostacyclin (PGI2) analogues. However, these agents also activate prostanoid EP1–4 receptor subtypes to varying degrees, which are positively (EP2/4) or negatively (EP3) coupled to adenylate cyclase through Gs or Gi, respectively. We investigated the role of these receptors in modulating relaxation to PGI2 analogues cicaprost, iloprost and treprostinil in pre-contracted segments of rat tail artery. Prostanoid IP (RO1138452), EP4 (GW627368X), EP3 (L-798106), EP1–3 (AH6809), and EP1 (SC-51322) receptor antagonists were used to determine each receptor contribution. The role of Gi/o was investigated using pertussis toxin (PTX), while dependence on cAMP was determined using adenylate cyclase (2′5′dideoxyadenosine, DDA) and protein kinase A (2′-O-monobutyryladenosine- 3′,5′-cyclic monophosphorothioate, Rp- isomer, Rp-2′-O-MB-cAMPS) inhibitors, and by measurement of tissue cAMP. All analogues caused relaxation which was significantly (P < 0.01) inhibited by RO1138452; with maximum response to cicaprost, iloprost and treprostinil reduced by 51%, 66% and 37%, respectively. GW627368X had no effect when used alone, but in combination with RO1138452, caused a rightward shift of the curves for cicaprost and iloprost but not treprostinil. PTX treatment potentiated relaxation to all 3 analogues (P < 0.01), as did L798106 and AH6809 but not SC-51322. Basal cAMP levels were higher in PTX-treated tissues and DDA- and Rp-2'-O-MB-cAMPs--sensitive responses increased to analogue concentrations < 0.1 μM. In conclusion, prostanoid EP3 receptors via Gi/o negatively modulate prostanoid IP receptor-mediated relaxation to cicaprost, iloprost and treprostinil. However, other pathways contribute to analogue-induced vasorelaxation, the nature of which remains unclear for treprostinil.
Keywords: PGI2 analogue; Prostanoid IP receptor; Prostanoid EP3 receptor; Prostanoid EP4 receptor; Gi/o, rat tail artery;
Effect of potassium channel opener pinacidil on the contractions elicited electrically or by noradrenaline in the human radial artery by Ljiljana Gojkovic-Bukarica; Natasa Savic; Miodrag Peric; Jasmina Markovic-Lipkovski; Sanja Cirovic; Vladimir Kanjuh; Jelena Cvejic; Milica Atanackovic; Aleksandar Lesic; Marko Bumbasirevic; Helmut Heinle (266-273).
In order to discover an agent that can prevent spasm of the human radial artery, the aim of our study was to evaluate the effect of the K+ channel opener, pinacidil, on contractions in the radial artery. Contractions of the radial artery were evoked by exogenously applied noradrenaline or by electrical field stimulation (EFS, 20 Hz, neurogenic). Pinacidil induced concentration-dependent inhibition of both EFS- and noradrenaline-evoked contractions of the radial artery. Glibenclamide, a selective blocker of ATP-sensitive K+ channels (Kir6.x containing subunit) antagonized in the same manner the pinacidil-induced inhibition of neurogenic contractions and contractions evoked by exogenous noradrenaline. The inhibition of pinacidil relaxation by tetraethylammonium (TEA), a blocker of Ca-sensitive K+ (KCa) channels, was more pronounced in EFS-contracted preparations. A blocker of voltage-sensitive K+ (KV) channels, 4-aminopyridine (4-AP), inhibited pinacidil relaxation only in EFS-contracted preparations. In order to test the presence of different K+ channels, immunohistochemistry of K+ channels expression in the radial artery was performed. The vascular wall of the human radial artery showed variable positivity with the following applied antibodies: Kv1.2, Kv1.3, Kir6.1, and KCa1.1. The antibodies against Kv1.6, Kv2.1, and Kir6.2 channel subunits were completely negative. These results suggest that the inhibitory effect of pinacidil on contractions of the human radial artery might be postsynaptic and associated with opening of smooth muscle Kir6.1-containing KATP channels. TEA- and 4-AP-sensitive K+ channels may also contribute to pinacidil effect in the human radial artery.
Keywords: Human radial artery; Electrical field stimulation; Immunohistochemistry; K+ channel; Pinacidil;
Minocycline attenuates ischemia-induced ventricular arrhythmias in rats by Xiaorong Hu; Bing Wu; Xin Wang; Changwu Xu; Bo He; Bo Cui; Zhibing Lu; Hong Jiang (274-279).
Minocycline has been shown to protect against myocardial ischemia–reperfusion injury. This study investigated the effects of minocycline on ischemia-induced ventricular arrhythmias in rats. Anesthetized male rats were once treated with minocycline (45 mg/kg, i.p.) 1 h before ischemia in the absence and/or presence of 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002, 0.3 mg/kg, i.v., a PI3K inhibitor) and 5-hydroxydecanoic acid [5-HD, 10 mg/kg, i.v., a specific inhibitor of mitochondrial ATP-sensitive potassium (KATP) channels] which were once injected 10 min before ischemia and then subjected to ischemia for 30 min. Ventricular arrhythmias were assessed. L-type Ca2+ current was measured by the patch-clamp technique. During the 30-minute ischemia, minocycline significantly reduced the incidence of ventricular fibrillation (VF) (P < 0.05). The duration of VT + VF, the number of VT + VF episodes and the severity of arrhythmias were all significantly reduced by minocycline compared to those in myocardial ischemia group (P < 0.05 for all). Administration of LY294002 or 5-HD abolished the protective effects of minocycline on VF incidence, the duration of VT + VF, the number of VT + VF episodes and the severity of arrhythmias (P < 0.05 for all). In addition, minocycline inhibited L-type Ca2+ currents of normal myocardial cell membrane in a dose-dependent manner. This study suggested that minocycline could attenuate ischemia-induced ventricular arrhythmias in rats in which PI3K/Akt signaling pathway, mitochondrial KATP channels and L-type Ca2+ channels may be involved.
Keywords: Minocycline; Ventricular arrhythmia; Myocardial ischemia; PI3K/Akt; Mitochondrial ATP-sensitive potassium; L-type Ca2+ channel;
Aldosterone alters the participation of endothelial factors in noradrenaline vasoconstriction differently in resistance arteries from normotensive and hypertensive rats by Fabiano E. Xavier; Javier Blanco-Rivero; María Soledad Avendaño; Esther Sastre; Rubén Yela; Kyra Velázquez; Mercedes Salaíces; Gloria Balfagón (280-288).
This study analyzed the effect of aldosterone (0.05 mg/kg per day, 3 weeks) on vasoconstriction induced by noradrenaline in mesenteric resistance arteries from WKY rats and SHR. Contraction to noradrenaline was measured in mesenteric resistance arteries from untreated and aldosterone-treatedrats from both strains. Participation of nitric oxide (NO), superoxide anions, thromboxane A2 (TxA2) and prostacyclin in this response was determined. 6-keto-prostaglandin (PG)F1alpha and thromboxane B2 (TxB2) releases were determined by enzyme immunoassay. NO and superoxide anion release were also determined by fluorescence and chemiluminiscence, respectively. Aldosterone did not modify noradrenaline-induced contraction in either strain. In mesenteric resistance arteries from both aldosterone-treated groups, endothelium removal or preincubation with NO synthesis inhibitor L-NAME increased the noradrenaline-induced contraction, while incubation with the superoxide anion scavenger tempol decreased it. Preincubation with either the COX-1/2 or COX-2 inhibitor (indomethacin and NS-398, respectively) decreased the noradrenaline contraction in aldosterone-treated animals, while this response was not modified by COX-1 inhibitor SC-560. TxA2 synthesis inhibitor (furegrelate), or TxA2 receptor antagonist (SQ 29 548) also decreased the noradrenaline contraction in aldosterone-treated animals. In untreated SHR, but not WKY rats, this response was increased by L-NAME, and reduced by tempol, indomethacin, NS-398 or SQ 29 548. Aldosterone treatment did not modify NO or TxB2 release, but it did increase superoxide anion and 6-keto-PGF(1alpha) release in mesenteric resistance arteries from both strains. In conclusion, chronic aldosterone treatment reduces smooth muscle contraction to alpha-adrenergic stimuli, producing a new balance in the release of endothelium-derived prostanoids and NO.
Keywords: Aldosterone; Mesenteric resistance artery; Nitric oxide; Superoxide anion; Thromboxane A2; Prostaglandin I2;
A protease inhibitor against acute stress-induced visceral hypersensitivity and paracellular permeability in rats by Juhui Zhao; Jinhai Wang; Lei Dong; Hongyang Shi; Zongyan Wang; Hui Ding; Haitao Shi; Xiaolan Lu (289-294).
In the present study, we investigated the effects of camostat mesilate (CM), a synthetic protease inhibitor, on visceral sensitivity and paracellular permeability induced by the acute restraint stress. We also explored the possible mechanisms underlying these effects. The acute restraint stress was induced by wrapping the fore shoulders, upper forelimbs and thoracic trunk of Sprague–Dawley rats for 2 h. Either CM (30, 100 and 300 mg/kg) or saline was intragastrically administrated to the rats 30 min before the acute restraint stress. Visceral perception was quantified as visceral motor response with an electromyography in a subset of rats. Paracellular permeability was determined in another subset of rats. We found that the visceral sensitivity and paracellular permeability were significantly reduced in the CM-treated rats. Moreover, the fecal protease activity was decreased in the CM-treated rats. The ZO-1 protein expression was markedly reduced by the stress treatment, but this decrease was suppressed by CM administration. Our data indicated that CM could efficiently inhibit visceral sensitivity and paracellular permeability induced by the acute restraint stress in rats. Therefore, CM might be an effective drug for the treatment of irritable bowel syndrome.
Keywords: Acute restraint stress; Paracellular permeability; Protease inhibitor; Visceral hypersensitivity;
Chronic or high dose acute caffeine treatment protects mice against oleic acid-induced acute lung injury via an adenosine A2A receptor-independent mechanism by Jun Li; Gongbo Li; Jian-Lin Hu; Xiao-Hong Fu; Yi-Jun Zeng; Yuan-Guo Zhou; Gang Xiong; Nan Yang; Shuang-Shuang Dai; Feng-Tian He (295-303).
The antagonism or genetic deletion of adenosine A2A receptors has been shown to exacerbate tissue damage in acute lung injury. Caffeine, a widely consumed behavioral drug, acts as a non-selective antagonist of A2A receptor and also has additional pharmacological effects. Thus, the protective vs. deleterious effects of caffeine in acute lung injury should be evaluated. In a murine oleic acid-induced model of acute lung injury, we found that chronic caffeine treatment by drinking water (0.1 g/l or 0.25 g/l for 2 weeks before acute lung injury) or acute caffeine treatment at high dose (i.p. 50 mg/kg, injection, 30 min before acute lung injury) significantly attenuated the lung edema, hemorrhage, neutrophil recruitment as well as the inflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) expressions in both of the wild type (WT) and A2A receptor knockout (KO) mice. This profile was accompanied by increased cAMP levels and up-regulation of A2B receptor mRNAs in the lungs. In contrast, acute caffeine treatment at low dose (i.p. 5 mg/kg or 15 mg/kg, injection, 30 min before acute lung injury) enhanced the inflammation and lung damage in WT mice with decreasing cAMP but not in A2A receptor KO mice. These results indicate that caffeine either enhances lung damage by antagonizing A2A receptor or exerts protection against lung damage via A2A receptor-independent mechanisms, depending on the timing of exposure (chronic vs. acute) and dose of administration (low vs. high). These findings provide new insight of caffeine in acute lung injury and highlight the potential benefit and strategy of caffeine intake or administration for preventing acute lung injury.
Keywords: Adenosine A2A receptor; Caffeine; Acute lung injury; Inflammation;
Therapeutic effects of TACI-Ig on collagen-induced arthritis by regulating T and B lymphocytes function in DBA/1 mice by Yunjie Liu; Lingling Zhang; Yingqi Wu; Tong Tong; Wendi Zhao; Peipei Li; Min Huang; Wenxiang Wang; Jianmin Fang; Wei Wei (304-314).
To investigate the abnormal function of T and B lymphocytes involved in collagen-induced arthritis in DBA/1 mice and the regulation role of TACI-Ig on T and B lymphocytes, collagen-induced arthritis models were established in DBA/1 mice. Mice were divided randomly into eight groups, including normal, collagen-induced arthritis model, TACI-Ig (0.350, 1.105, 3.333, 10, and 30 mg/kg) and IgG-Fc (10 mg/kg) treated groups. The effect of TACI-Ig on collagen-induced arthritis was evaluated by arthritis scores, joints and spleens histopathology, paws radiology, and indices of thymus and spleen. T and B lymphocyte proliferations were assayed by [3H]-TdR method. B lymphocyte stimulator and prostaglandin E2 in serum were assayed by enzyme linked immunosorbent assay. The subsets of T and B lymphocytes were assayed by flow cytometry. Results showed that the onset of paw-swelling was on day 31 after immunization. The peak of inflammation appeared on day 42 and then declined after day 63. Compared with normal mice, collagen-induced arthritis mice have increased arthritis scores, spleen and thymus indices, radiograph scores of joints, and pathology scores of joints and spleens. TACI-Ig could ameliorate these changes and reduce the increased serum level of B lymphocyte stimulator and prostaglandin E2. Further studies showed that TACI-Ig inhibited T and B lymphocyte proliferation response, and inhibited differentiation and activity of T and B lymphocytes in collagen-induced arthritis mice. In conclusion, TACI-Ig has a good therapeutic action on collagen-induced arthritis mice, which might be related to the regulation of TACI-Ig on inflammation mediators and abnormal function of T and B lymphocytes.
Keywords: Rheumatoid arthritis; TACI-Ig; B lymphocyte stimulator; Lymphocyte; Collagen-induced arthritis;
Activation of T cell death-associated gene 8 attenuates inflammation by negatively regulating the function of inflammatory cells by Yoshiko Onozawa; Tomoaki Komai; Tomiichiro Oda (315-319).
T cell death-associated gene 8 (TDAG8) is a G-protein-coupled receptor identified by differential mRNA display during thymocyte apoptosis induced by T cell receptor engagement. To examine the physiological role of an orphan G-protein-coupled receptor TDAG8 in inflammation, we studied various immune-mediated inflammatory disease models using TDAG8-deficient mice. We found that TDAG8-deficient mice showed significant exacerbation of anti-type II collagen antibody-induced arthritis and delayed-type hypersensitivity, and showed a slight exacerbation of collagen-induced arthritis. These results suggest that TDAG8 acts as a negative regulator of inflammation.
Keywords: T cell death-associated gene 8; G-protein-coupled receptor; Knockout mouse; Anti-type II collagen antibody-induced arthritis; Delayed-type hypersensitivity; Collagen-induced arthritis;
Amelioration effects of berberine on diabetic microendothelial injury model by the combination of high glucose and advanced glycation end products in vitro by Min Hao; Shu-yuan Li; Chang-kai Sun; Jingyu-Xu; Yuan Lin; Ke-xin Liu; Li Wang; Chuan-xun Li; Qin Zhou; Jian-ling Du; Hua Li (320-325).
Microvascular complications are much earlier and common in diabetes. Advanced glycation end products (AGEs), together with high glucose, play a key role in the endothelial dysfunction of diabetic vascular complications. So it is of more significance to expedite the therapies to block the formation and/or the effects of AGEs. Berberine has been showed to have anti-diabetic effects, however the effects on diabetic complications were less explored, especially the effects on the microvascular complications and the formation and pathways of AGEs which have not been reported. Therefore, the present study established an in vitro model of diabetic microendothelial (microEC) injury by the combination of high glucose and AGEs to mimic the clinical situations and examine the effects and mechanisms of berberine on high glucose-AGEs-induced microEC injuries and on the formation of AGEs. We prepared AGEs, established the high glucose-AGEs injured microEC models by MTT assay, which was further supported by significantly decreased nitric oxide (NO) release, NO synthase (NOS) and thrombomodulin production with ELISA, western blot and RT-PCR analysis. Berberine treatments showed significant improvements as indicated by significantly increased NO release, NOS and thrombomodulin production. Moreover, we also observed significant inhibition effects of berberine on AGEs formation. We concluded that the in vitro model of diabetic microEC injury could be established by the combination treatments of high glucose and AGEs, while berberine could improve the diabetic microvascular injury in vitro and inhibit the formation of AGEs, suggesting the potential clinical therapies with berberine for diabetes and its vascular complications.
Keywords: Berberine; Advanced glycation end products; Microendothelial cell; Thrombomodulin; Diabetes;