European Journal of Pharmacology (v.545, #2-3)

Previous studies have shown that “Mudanpi”, a Chinese herbal medicine, has a significant cardioprotective effect against myocardial ischaemia. Based on these findings we hypothesised that paeonol, the main component of Mudanpi, might have an effect on the cellular electrophysiology of cardiac ventricular myocytes. The effects of paeonol on the action potential and ion channels of cardiac ventricular myocytes were studied using the standard whole-cell configuration of the patch-clamp technique. Ventricular myocytes were isolated from the hearts of adult guinea-pig by enzymic dispersion. The myocytes were continuously perfused with various experimental solutions at room temperature and paeonol applied in the perfusate. Action potentials and membrane currents were recorded using both current and voltage clamp modes of the patch-clamp technique. Paeonol, at concentrations 160 μM and 640 μM, decreased the action potential upstroke phase, an action associated with the blockade of the voltage-gated, fast sodium channel. The effects of paeonol on both action potential and Na+ current were concentration dependent. Paeonol had a high affinity for inactivated sodium channels. Paeonol also shortened the action potential duration, in a manner not associated with the blockade of the calcium current, or the enhancement of potassium currents. These findings suggest that paeonol, and therefore Mudanpi, may possess antiarrhythmic activity, which may confer its cardioprotective effects.
Keywords: Paeonol; Action potential; Sodium current; Ventricular myocyte; Whole-cell patch-clamp;

Selective conjugated fatty acids inhibit guinea pig platelet aggregation by Guangming Li; Daniel Butz; Baiyan Dong; Yeonhwa Park; Michael W. Pariza; Mark E. Cook (93-99).
Conjugated linoleic acids have been shown to reduce eicosanoid release from select tissues and/or cells. To elucidate effects of conjugated linoleic acid isomers on cyclooxygenase-1 (COX-1) activity and their application as platelet aggregation inhibitors, conjugated linoleic acid isomers and conjugated nonadecadienoic acid were incubated with ovine COX-1 and Raw264.7 macrophage to examine their effects on COX-1 activity. The effects were further examined in collagen and ADP-induced guinea pig whole blood platelet aggregation. Fatty acids tested were shown to inhibit COX-1 enzymatic activity. However, only 10t, 12c-conjugated linoleic acid, 9t, 11t-conjugated linoleic acid and conjugated nonadecadienoic acid inhibited collagen and ADP-induced platelet aggregation with IC50 125.9 μM (74.2 μM to 213.4 μM, 95% confidence interval), 99.3 μM (52.8 μM to 187.2 μM, 95% confidence interval) and 124.3 μM (85.1 μM to 181.5 μM, 95% confidence interval) respectively in collagen-induced aggregation. TxB2 release was also appreciably inhibited by 10t, 12c-conjugated linoleic acid, 9t, 11t-conjugated linoleic acid and conjugated nonadecadienoic acid. Based on these data, we conclude 10t, 12c-conjugated linoleic acid, 9t, 11t-conjugated linoleic acid and conjugated nonadecadienoic acid are platelet aggregation inhibitors while 9c, 11t-conjugated linoleic acid is a moderate inhibitor and linoleic acid, and 9c, 11c-conjugated linoleic acid have no effect on whole blood platelet aggregation.
Keywords: Conjugated linoleic acid; Conjugated nonadecadienoic acid; Isomer; Cyclooxygenase; Platelet aggregation;

Thromboxane A2 receptor-mediated G12/13-dependent glial morphological change by Shigeyoshi Honma; Manami Saika; Satoko Ohkubo; Hitoshi Kurose; Norimichi Nakahata (100-108).
Glial cells express thromboxane A2 receptor, but its physiological role remains unknown. The present study was performed to examine thromboxane A2 receptor-mediated morphological change in 1321N1 human astrocytoma cells. Thromboxane A2 receptor agonists U46619 and STA2 caused a rapid morphological change to spindle shape from stellate form of the cells pretreated with dibutyryl cyclic AMP, but neither carbachol nor histamine caused the change, suggesting that Gq pathway may not mainly contribute to the change. Rho kinase inhibitor Y-27632 inhibited U46619-induced morphological change, and U46619 increased the GTP-bound form of RhoA accompanied with actin stress fiber formation. These responses were reduced by expression of p115-RGS that inhibits G12/13 signaling pathway. U46619 also caused the phosphorylation of extracellular signal-regulated kinase (ERK) and [3H]thymidine incorporation mainly through G12/13-Rho pathway. These results suggest that stimulation of thromboxane A2 receptor causes the morphological change with proliferation mainly through G12/13 activation in glial cells.
Keywords: Thromboxane A2 receptor; G12 family G protein; Rho; Proliferation; ERK;

The signal transduction pathways of intracellular calcium and adenosin 3′,5′-cyclic monophosphate (cAMP) participate in the regulation of intrahepatic metabolism of very low density lipoproteins (VLDL). The adrenoceptors are linked to calcium and cAMP signal transduction pathways so it is proposed that they may be involved in the regulation of VLDL secretion. The current study is designed to test the effects of α- and β-adrenoceptor agonists and antagonists on triacylglycerol secretion in freshly isolated rat hepatocytes.The inhibitory effect of epinephrine appeared at concentrations of more than 1 μM and reached a plateau at 100 μM. Epinephrine concentration for the half of the maximal bio-effect (EC50) was about 10 μM. Epinephrine at a concentration of 10 μM suppressed the secretion of triacylglycerol by 33% (P  ≤ 0.01) and increased cellular content of triacylglycerol (18%, P  ≤ 0.05) and total phospholipids (20%, P  ≤ 0.05). Time course experiments for triacylglycerol secretion exhibited a linear relationship with a slope of 8.2 ± 0.6 μg triacylglycerol/3 h mg cell protein. In the presence of epinephrine, cellular triacylglycerol and total phospholipids were slightly but significantly higher than the respective control at all points of time examined.The inhibitory effect elicited by epinephrine (10 μM) was abolished by the inclusion of the general α-adrenoceptor antagonist phentolamine (10 μM) and the specific α1-antagonist prazosin (1 μM) but not with the nonselective β-antagonist propranolol (10 μM). Trifluoperazine an α-adrenoceptor antagonist and anticalmodulin agent, concealed the inhibitory effect of epinephrine in a concentration dependent manner, whereas theobromine a cAMP-phosphodiestrase inhibitor did not have any significant effect. The secretion of triacylglycerol was decreased not only by the α-adrenoceptor agonist phenylephrine (10 μM) but also by the β-agonist isoproterenol (10 μM). Dibutyryl-cAMP (0.1 mM) also inhibited the secretion of triacylglycerol by 30% (P  ≤ 0.01). The results suggest that epinephrine inhibits the secretion of triacylglycerol from rat hepatocytes via the α1-adrenoceptor while stimulation of β- as well as α-adrenoceptors can also exert a similar effect.
Keywords: Adrenoceptor; Cyclic AMP; Epinephrine; Isoproterenol; Triacylglycerol; VLDL;

Influence of external and intracellular pH on propofol-induced responses in rat locus coeruleus neurons by Chien-Liang Chen; Jing-Shia Tang; Tsai-Hsien Chiu; Yea-Ru Yang (115-122).
The effect of external and intracellular pH on propofol-induced responses in rat locus coeruleus neurons was examined using intracellular recording from in vitro brain slice preparations. Experimental variation of external pH from 7.34 to 6.81 did not affect the propofol-induced responses. In contrast, raising the external pH from 7.34 to 8.10 resulted in enhanced 100 μM propofol effects. The effects were 1.8 times greater on membrane hyperpolarization (pH 8.10: 11.8 ± 1.3 mV; pH 7.34: 6.5 ± 1.0 mV, n  = 5) and 1.5 times greater on reduction in input resistance (pH 8.10: 38.2 ± 6.3%; pH 7.34: 24.7 ± 4.1%, n  = 5). Cytosolic acidification was used in which 1/3 NaCl in artificial cerebrospinal fluid was replaced with weak organic acids–sodium acetate. It did not significantly affect the propofol-induced responses. On the other hand, intracellular alkalinization with 5 mM NH4Cl markedly suppressed the 100 μM propofol-induced membrane hyperpolarization (1.0 ± 0.6 mV; control: 13.9 ± 0.9 mV, n  = 5) and reduction of input resistance (38.1 ± 1.3%; control: 61.0 ± 4.3%, n  = 5). However, the presence of 3–5 mM ammonium acetate also showed the similarly suppressing effect on membrane hyperpolarization (1.7 ± 0.6 mV; control: 9.2 ± 1.8 mV, n  = 5) and reduction of input resistance (28.5 ± 8.5%; control: 37.0 ± 6.3%, n  = 5) caused by 100 μM propofol. We suggested that the main suppressing effect of NH4Cl results from ammonium ion, but not intracellular alkalinization. Furthermore, we examined the feature of pharmacological regulation of propofol-induced responses by pentobarbital or alphaxalone during pH changes. It appears that neither pentobarbital nor alphaxalone could allosterically modulate the propofol-induced responses, which had been affected by pH changes.
Keywords: Locus coeruleus; Propofol; pH change;

The effect of lithium chloride on morphine-induced tolerance and dependence in isolated guinea pig ileum by Afsaneh Alborzi; Shahram Ejtemaei Mehr; Fatemeh Rezania; Setareh Badakhshan; Tajmah Mombeini; Hamed Shafaroodi; Leila Moezi; Mohammadreza Nick Ravan; Mahdiyeh Sharifian; Ahmad Reza Dehpour (123-128).
The chronic use of opioids is often accompanied by the development of tolerance and/or dependence upon these agents due to the adaptive changes in the response of the subject to the agent. On cellular level, these phases of altered responsiveness have been shown to be the sequelae of a combination of multiple independent components acting in concert. Changes in the number, affinity, or membrane trafficking of opioids receptors, the coupling of receptors to G-proteins or in associated second messenger systems have been implicated in underlying the aforementioned phenomena. Several observations have been shown that lithium is able to contradict the expected response in animals pre-treated with morphine. These facts clearly manifest the involvement of lithium in at least one of the diverse pathways that lead to morphine dependence and/or tolerance. The aim of the present study was to investigate the effect of lithium on acute morphine-induced tolerance and dependence in an in vitro model of isolated guinea pig ileum which has been extensively used for the assessment of these effects of opioids. Morphine inhibited electrically stimulated twitch of ileum in a concentration-dependent manner (pD 2  = 7.27 ± 0.16). Tolerance to this effect was induced by the incubation of ileum with 2 × IC50 of morphine for 2 h that induced a degree of tolerance of 14.7. The co-incubation of ileum with morphine along lithium chloride (1 mM) reduced the degree of tolerance significantly (P  < 0.001) and restored the sensitivity of ileum to the morphine inhibitory effect. Lithium chloride can also reduce the expression of tolerance to morphine significantly (P  < 0.01). Dependence was induced by incubation with 4 × IC50 of morphine for 2 h and was assessed based on naloxone-induced contractions (10− 5 M). Lithium chloride (1 mM) can attenuate the development but not the expression of dependence to morphine as shown by the significant decrease in naloxone-induced contractions (P  < 0.05). These results suggest that lithium chloride can reduce the development and expression of acute tolerance to and development of dependence on morphine in the myenteric plexus of guinea pig ileum.
Keywords: Ileum; Guinea pig; Tolerance; Dependence; Morphine; Lithium;

The antinociceptive effect of Salvinorin A in mice by Trentini F. John; Larry G. French; Joseph S. Erlichman (129-133).
Salvia divinorum is a hallucinogenic plant used by the Mazatec Indians of Mexico for traditional spiritual ceremonies. The active constituent, salvinorin A, induces profound hallucinations, however the biological mechanism for this action is not known. Affinity-binding studies suggest that the biologic activity of salvinorin A involves the κ-opioid receptor. The purpose of this study was to evaluate the antinociceptive effect of salvinorin A in mice. Salvinorin A and opioid receptor antagonists were administered intrathecally and the tail-flick latencies were used as a measure of antinociception. Salvinorin A increased tail-flick latencies in a dose-dependent manner (13.9–23.1 nmol) compared to control trials. Pretreatment with the κ-opioid receptor antagonist nor-binaltorphimine attenuated the salvinorin A induced increase in tail-flick latency. In contrast, neither the μ-opioid receptor antagonist β-funaltrexamine nor δ-opioid receptor antagonist naltrindole significantly affected the antinociceptive response of salvinorin A administration. These data support previous reports that salvinorin A represents a unique non-alkaloidal agonist for the κ-opioid receptor.
Keywords: Salvinorin A; Kappa opioid receptor; Antinociception;

Changes in mGlu5 receptor expression in the basal ganglia of reserpinised rats by Naila Ismayilova; Alexei Verkhratsky; Michael J. Dascombe (134-141).
Dopamine depletion in Parkinson's disease results in a series of pathophysiological changes in the basal ganglia circuitry. Increased release of glutamate plays an important role in this motor disorder, therefore, agents interacting with glutamatergic transmission may have therapeutic potential. In this study we investigated changes in both mRNA expression and the number of binding sites of the mGlu5 receptor in a reserpinised rat model of Parkinson's disease. The in situ hybridisation demonstrated that acute reserpine treatment caused a significant decrease in the expression of mGlu5 receptor mRNA in the rostral and caudal parts of the rat striatum. At the same time, tritium-labelled 2-ethyl-6-(phenylethynyl)-pyridine ([3H]MPEP) ligand binding experiments detected a significant increase in the total number of mGlu5 receptors in the same region of the motor loop. These apparently contradictory data can be explained by mGlu5 receptor turnover being down-regulated in reserpinised rats, due possibly to an imbalance in the rates of synthesis/insertion and internalisation/degradation of the receptor. These findings suggest that changes such as these affecting mGlu5 receptors may be involved in the pathophysiological consequences of dopamine depletion in the brain.
Keywords: mGlu5 receptor; ‘in situ’ hybridisation; mRNA; [3H]MPEP ligand binding; Reserpine; Rat; Parkinson's disease;

Valproate prevents MK801-induced changes in brain-derived neurotrophic factor mRNA in the rat brain by Gye Sun Jeon; Sang-Ha Park; Kuem-Ju Lee; Min-Soo Lee; Boe-Gwun Chun; Kyung-Ho Shin (142-146).
To investigate whether the anticonvulsant valproate influences the changes in brain-derived neurotrophic factor (BDNF) mRNA expression induced by MK801 in rat brain, we injected valproate prior to MK801 and observed the changes in the BDNF expression 3 h later. MK801 significantly increased BDNF expression in the retrosplenial and entorhinal cortex, and these increases were prevented by valproate pretreatment. Valproate pretreatment significantly blocked the MK801-induced increase of BDNF expression in retrosplenial cortex at 3 h, 6 h, and 9 h after MK801 injection, suggesting that valproate pretreatment did not delay the MK801-induced increase of BDNF expression. However, MK801 significantly decreased BDNF expression in the granule cell layer of hippocampus, and valproate pretreatment before MK801 potentiated the MK801-induced decrease in BDNF expression in granule cell layer. These results indicate that valproate pretreatment differentially affects the MK801-induced changes in BDNF expression in a region-selective manner.
Keywords: BDNF (brain-derived neurotrophic factor); MK801; Valproate; Retrosplenial cortex;

The μ-opioid receptor subtype is required for the anorectic effect of an opioid receptor antagonist by Jiaping Zhang; Andrea Frassetto; Ruey-Ruey C. Huang; Julie Z. Lao; Alexander Pasternak; Sheng-ping Wang; Joseph M. Metzger; Alison M. Strack; Tung M. Fong; Richard Z. Chen (147-152).
A diaryl ether derivative, (6-(4-{[(3-methylbutyl)amino]methyl}phenoxy)nicotinamide, was prepared and investigated for its biochemical properties at cloned opioid receptors and its pharmacological effects on animal feeding. The compound displaced [3H]DAMGO binding of human μ-opioid receptor, [3H]U-69593 of human κ-opioid receptor, and [3H]DPDPE of human δ-opioid receptor with IC50 values of 0.5 ± 0.2 nM, 1.4 ± 0.2 nM, and 71 ± 15 nM, respectively. The compound also potently inhibited [3H]DAMGO binding of cloned mouse and rat μ-opioid receptors (IC50  ≈ 1 nM), and acted as a competitive antagonist in a cAMP functional assay using cultured cells expressing human or mouse μ-opioid receptors. Following a single oral administration in diet-induced obese mice (at 10 or 50 mg/kg) or rats (at 1, 3, or 10 mg/kg), the compound caused a dose-dependent suppression of acute food intake and body weight gain in both species. Importantly, the anorectic efficacy of the compound was mostly diminished in mice deficient in the μ-opioid receptor. Our results suggest an important role for the μ-opioid receptor subtype in animal feeding regulation and support the development of μ-selective antagonists as potential agents for treating human obesity.
Keywords: Opioid receptor antagonist; Knockout mice; Food intake; Body weight;

Characterisation of the relaxant response to raloxifene in porcine coronary arteries by Alkje Moritz; Oliver A. Radtke; Ronald Gust; Erika Glusa; Heinz H. Pertz (153-160).
The present study characterises the vasorelaxant response to raloxifene in isolated rings of porcine coronary artery. Tissues precontracted either with KCl (30 mM) or prostaglandin F (PGF; 3 μM) were concentration-dependently relaxed by raloxifene (0.1–10 μM). Relaxation was not inhibited by the estrogen receptor antagonist 7α-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]-estra-1,3,5(10)-triene-3,17β-diol (ICI 182,780; 1 μM). Preincubation with raloxifene (1–3 μM) caused an inhibition of the KCl or PGF-induced contraction. The effects of raloxifene were independent of the endothelium. The relaxant response to raloxifene was slow in the onset and could not be reversed after repeated washings. Raloxifene did not affect Ca2+ release from intracellular stores since it failed to inhibit a transient contraction induced by caffeine (10 mM). Raloxifene-induced relaxation was not influenced by the intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM; 10–20 μM). Calcium-induced contractions in Ca2+-free high K+ (60 mM) depolarising medium were concentration-dependently inhibited by raloxifene (0.3–3 μM). If arterial rings were incubated with the L-type Ca2+ channel activator (S)-(–)-1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-3-pyridine carboxylic acid methyl ester ((S)-(–)-Bay K 8644; 0.1 μM), cumulative concentration–response curves to Ca2+ were shifted to the left. Raloxifene (0.3–3 μM) inhibited the effect of (S)-(–)-Bay K 8644 in a concentration-dependent manner. 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole (SB 203580; 10 μM), an inhibitor of p38 mitogen-activated protein kinase (MAPK), diminished raloxifene-induced relaxation in endothelium-denuded arterial rings. Western blot analysis demonstrated that raloxifene stimulated p38 MAPK. It is concluded that raloxifene has an inhibitory effect on voltage-gated and receptor-operated L-type Ca2+ channels in porcine coronary arteries, thus inducing vascular relaxation independent of the endothelium. p38 MAPK is, at least in part, involved in the relaxant response to raloxifene.
Keywords: Ca2+ channels; Endothelium; p38 MAPK (p38 mitogen-activated protein kinase); Porcine coronary arteries; Raloxifene; Vasorelaxation;

Chlorzoxazone inhibits contraction of rat thoracic aorta by De-Li Dong; Yan Luan; Tie-Ming Feng; Chang-Long Fan; Peng Yue; Zhi-Jie Sun; Rui-Min Gu; Bao-Feng Yang (161-166).
Chlorzoxazone has been reported to activate the intermediate-conductance, Ca2+-activated K+ channels in aortic endothelial cells and to relax the artery. The aim of the present study was to characterize the chlorzoxazone-induced relaxation of rat thoracic artery. Chlorzoxazone did not affect the tension of the thoracic artery rings at rest, but relaxed the precontraction induced by 1 μM noradrenaline in an endothelium independent manner. Preincubation with chlorzoxazone also antagonized the contraction induced by 1 μM noradrenaline or 25 mM KCl. The chlorzoxazone-induced relaxation of the thoracic artery pre-contracted by noradrenaline was suppressed by 5 mM tetraethylammonium, 75 mM ethanol and 2 μM paxilline, but not by 2 μM clotrimazole. Chlorzoxazone relaxed the 4-aminopyridine-induced contraction. The pattern of chlorzoxazone-induced relaxation was different from that of verapamil, the L-type Ca2+ channel blocker. The inhibition of the noradrenaline-induced contraction by chlorzoxazone was attenuated when chlorzoxazone treatment was prolonged to 4 h. No difference in the contraction–relaxation was found between the artery rings from normal rats and those from rats that received 100 mg/kg chlorzoxazone for 7 days. We conclude that chlorzoxazone abolishes the contraction of rat thoracic artery induced by noradrenaline and that the effect of chlorzoxazone is endothelium independent and also not mediated by intermediate-conductance, Ca2+-activated K+ channels.
Keywords: Chlorzoxazone; Ca2+-activated K+channel; Thoracic artery; Relaxation;

Ranbezolid, a novel oxazolidinone antibacterial: In vivo characterisation of monoamine oxidase inhibitory potential in conscious rats by Krishna S. Naruganahalli; Raj K. Shirumalla; Vimal Bansal; Jung B. Gupta; Biswajit Das; Abhijit Ray (167-172).
Ranbezolid, a novel oxazolidinone antibacterial, competitively inhibits monoamine oxidase-A (MAO-A), in vitro. The consequences of MAO-A inhibition was evaluated in vivo, by testing interaction of Ranbezolid with tyramine (in solution or mixed with feed), and amine containing cold remedies on pressor response in conscious rats. Single and repeat doses of Ranbezolid (50 mg/kg, p.o.) did not affect pressor response to tyramine (5 or 15 mg/kg), but potentiated the same after a single dose of 100 mg/kg. Co-administration of Ranbezolid with tyramine in feed or with cold remedies also did not potentiate the respective pressor responses. These results suggest that Ranbezolid exhibits minimal cardiovascular liability associated with MAO-A inhibition.
Keywords: Ranbezolid; Pressor response; Tyramine; Oxazolidinone; Cold remedies;

Improvement of walking disturbance by beraprost sodium in rat femoral artery occlusion models by Mitsuko Miyamoto; Toshikazu Tayama; Sin'ichi Yamaguchi; Masayuki Kaneko; Hajimu Kurumatani (173-176).
In rats receiving bilateral femoral arteries ligation (day 0), repeated oral administration of the prostacyclin derivative beraprost sodium (50 μg/kg, b.i.d.) from day 1 to day 5 resulted in a significant prolongation in walking time in rotarod walking exercise performed on day 5. Similarly, results were obtained in rats with bilateral femoral arterial thrombosis induced by application of FeCl3/HCl. In the ligation model, a significant increase was observed in femoral/carotid arterial blood pressure ratio even on day 2. These results indicated that beraprost sodium improves blood flow and walking disturbances associated with arterial occlusion in rats.
Keywords: Beraprost sodium; Intermittent claudication; Walking disturbance;

N-hexacosanol reverses diabetic induced muscarinic hypercontractility of ileum in the rat by Chiko Shinbori; Motoaki Saito; Yukako Kinoshita; Itaru Satoh; Tomoharu Kono; Takuya Hanada; Eiji Nanba; Kaori Adachi; Hiroto Suzuki; Masashi Yamada; Keisuke Satoh (177-184).
Diabetic neuropathy, a major complication of diabetes mellitus, is associated with development of gastrointestinal motility dysfunction and autonomic neuropathy. N-hexacosanol has neurotrophic effects and exhibits a wide variety of biological actions. In this study, we investigated the effects of cyclohexenonic long-chain fatty alcohol (N-hexacosanol) on streptozotocin-diabetic hypercontractility in the rat ileum longitudinal muscles. Treatment with N-hexacosanol did not alter the diabetic status of the animals, i.e., body weight, serum glucose, and serum insulin levels, but significantly restored the thickness of intestine wall and ameliorated diabetes-induced hypercontractility of the rat ileum in a dose-dependent manner. Furthermore, N-hexacosanol reversed the diabetes-induced upregulation of intestinal muscarinic M2 and M3 receptors mRNAs in the streptozotocin-diabetic rats. These results indicate that N-hexacosanol has therapeutic effects on hypercontractility in the diabetic ileum by ameliorating overexpression of muscarinic M2 and M3 receptors mRNAs.
Keywords: Diabetes; Neuropathy; Muscarinic M2 receptor; Muscarinic M3 receptor; mRNA; Cyclohexenonic long-chain fatty alcohol;

Effect of tamsulosin on spontaneous bladder contraction in conscious rats with bladder outlet obstruction: Comparison with effect on intraurethral pressure by Akiyoshi Ohtake; Masashi Ukai; Chikashi Saitoh; Rie Sonoda; Yukiko Noguchi; Hiroko Okutsu; Hironori Yuyama; Shuichi Sato; Masao Sasamata; Keiji Miyata (185-191).
We investigated the effect of tamsulosin, an α1-adrenoceptor antagonist, on bladder function, especially spontaneous bladder contractions before micturition (premicturition contraction), in conscious rats with bladder outlet obstruction induced by partial urethral ligation, and compared the results with the effect on intraurethral pressure response in anesthetized rats. In obstructed rats, the α1-adrenoceptor antagonists tamsulosin, naftopidil and urapidil and non-selective α-adrenoceptor antagonist phentolamine inhibited premicturition contractions in a dose-dependent fashion. In contrast, yohimbine, an α2-adrenoceptor antagonist, and atropine, a muscarinic receptor antagonist, hardly inhibited them. Tamsulosin and urapidil showed clearly inhibitory effects on increases in intraurethral pressure induced by phenylephrine, an α1-adrenoceptor agonist, in the same dose range as that at which they inhibited premicturition contractions, whereas naftopidil required somewhat higher doses to inhibit increases in intraurethral pressure than those at which it inhibited premicturition contractions. In conclusion, premicturition contractions observed in obstructed rats were sensitive to α1-adrenoceptor antagonists, but not to α2-adrenoceptor or muscarinic receptor antagonists. Tamsulosin was shown to be effective against both premicturition contraction and intraurethral pressure response in the same dose range in rats. These results partly support the fact that tamsulosin has improved storage symptoms as well as voiding symptoms in patients with lower urinary tract symptoms associated with bladder outlet obstruction by blocking α1-adrenoceptors.
Keywords: Tamsulosin; α1-Adrenoceptor; Intraurethral pressure; Premicturition contraction; Bladder outlet obstruction;

Cordycepin inhibits lipopolysaccharide-induced inflammation by the suppression of NF-κB through Akt and p38 inhibition in RAW 264.7 macrophage cells by Ho Gyoung Kim; Bhushan Shrestha; So Yeon Lim; Deok Hyo Yoon; Woo Chul Chang; Dong-Jik Shin; Sang Kuk Han; Sang Min Park; Jung Hee Park; Hae Il Park; Jae-Mo Sung; Yangsoo Jang; Namsik Chung; Ki-Chul Hwang; Tae Woong Kim (192-199).
Cordyceps militaris, a caterpillar-grown traditional medicinal mushroom, produces an important bioactive compound, cordycepin (3′-deoxyadenosine). Cordycepin is reported to possess many pharmacological activities including immunological stimulating, anti-cancer, anti-virus and anti-infection activities. The molecular mechanisms of cordycepin on pharmacological and biochemical actions of macrophages in inflammation have not been clearly elucidated yet. In the present study, we tested the role of cordycepin on the anti-inflammation cascades in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. In LPS-activated macrophage, nitric oxide (NO) production was inhibited by butanol fraction of C. militaris and the major component of C. militaris butanol faction was identified as cordycepin by high performance liquid chromatography. To investigate the mechanism by which cordycepin inhibits NO production and inducible nitric oxide synthase (iNOS) expression, we examined the activation of Akt and MAP kinases in LPS-activated macrophage. Cordycepin markedly inhibited the phosphorylation of Akt and p38 in dose-dependent manners in LPS-activated macrophage. Moreover, cordycepin suppressed tumor necrosis factor (TNF-α) expression, IκB alpha phosphorylation, and translocation of nuclear factor-κB (NF-κB). The expressions of cycloxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were significantly decreased in RAW 264.7 cell by cordycepin. Taken together, these results suggest that cordycepin inhibits the production of NO production by down-regulation of iNOS and COX-2 gene expression via the suppression of NF-κB activation, Akt and p38 phosphorylation. Thus, cordycepin may provide a potential therapeutic approach for inflammation-associated disorders.
Keywords: Cordyceps militaris; Cordycepin; Macrophage; Inflammation; NO production; Lipopolysaccharide (LPS);

Author index (200-201).

Keyword index (202-205).