European Journal of Pharmacology (v.523, #1-3)
Editorial Board (ii).
Interferon and the central nervous system by Nachum Dafny; Pamela B. Yang (1-15).
Interferons (IFNs) were discovered as natural antiviral substances produced during viral infection and were initially characterized for their ability to “interfere” with viral replication, slow cell proliferation, and profound alteration of immunity. The IFNs are synthesized and secreted by monocytes, macrophages, T-lymphocytes, neurons, and glia cells. The different IFNs are classified into three classes: alpha, beta, and gamma. α-IFN produced in the brain exerts direct effects on the brain and endocrine system by activating the neurosecretory hypothalamic neurons and regulates the hypothalamic–pituitary–adrenocortical axis. IFNs modulate neurophysiological activities of many brain region involving in pain, temperature, and food intake regulation. α-IFN administration activates the sympathetic nerves innervating components of the immune system. IFNs may serve as regulatory mediators between the central nervous system, the immune system, and endocrine system. IFN is used as immunologic therapy to treat various hematologic malignancies and infectious ailments and autoimmune diseases.
Keywords: Interferon alpha; Beta; Gamma; Immune; Endocrine; Sleep; Food; Temperature; Glucose sensitive; Opiate; Naloxone;
Inhibitory action of L-type Ca2+ current by paeoniflorin, a major constituent of peony root, in NG108-15 neuronal cells by Tung-Ying Tsai; Sheng Nan Wu; Yen-Chin Liu; Adonis Z. Wu; Yu-Chuan Tsai (16-24).
The effects of paeoniflorin, a glycoside isolated from the root of Paeonia lactiflora, on ion currents in a mouse neuroblastoma and rat glioma hybrid cell line, NG108-15 were investigated. Paeoniflorin (1–300 μM) reversibly produced an inhibition of L-type voltage-dependent Ca2+ current (I Ca,L) in a concentration-dependent manner. Paeoniflorin caused no change in the overall shape of the current–voltage relationship of I Ca,L. The IC50 value of paeoniflorin-induced inhibition of I Ca,L was 14 μM. However, neither adenosine deaminase (1 U/ml) nor 8-cyclopentyl-1, 3-dipropylxanthine (10 μM) could reverse the inhibition by paeoniflorin of I Ca,L. Paeoniflorin (30 μM) shifted the steady-state inactivation curve of I Ca,L to more negative membrane potentials by approximately − 10 mV. It also prolonged the recovery of I Ca,L. The inhibitory effect of paeoniflorin on I Ca,L exhibited tonic and use-dependent characteristics. Paeoniflorin could effectively suppress I Ca,L evoked by action potential waveforms. Paeoniflorin at a concentration of 30 μM produce a slight inhibition of voltage-dependent Na+ current and delayed rectifier K+ current. Under current-clamp configuration, unlike adenosine, this compound decreased the firing of action potentials. Taken together, this study indicates that paeoniflorin can block L-type Ca2+ channels in NG108-15 cells in a mechanism unlinked to the binding to adenosine receptors. The effects of paeoniflorin on ion currents may partly, if not entirely, contribute to the underlying mechanisms through which it affects neuronal or neuroendocrine function.
Keywords: Paeoniflorin; L-type Ca2+ current; NG108-15 cells;
Enhancement of alcohol dehydrogenase activity in vitro by acetylsalicylic acid by Munetaka Negoro; Ichiro Wakabayashi (25-28).
The interaction of acetylsalicylic acid with alcohol dehydrogenase was investigated. Horse liver alcohol dehydrogenase bound to a p-hydroxyacetophenone affinity column was eluted by acetylsalicylic acid. In vitro enzymatic activity of alcohol dehydrogenase in the presence of ethanol as a substrate was significantly increased by incubation with acetylsalicylic acid. These results suggest that acetylsalicylic acid has an affinity with alcohol dehydrogenase and enhances its activity.
Keywords: Acetylsalicylic acid; Alcohol dehydrogenase; p-Hydroxyacetophenone;
The novel analgesic, F 13640, produces intra- and postoperative analgesia in a rat model of surgical pain by Ivan Kiss; Anne-Dominique Degryse; Laurent Bardin; Ignacio Alvarez Gomez de Segura; Francis C. Colpaert (29-39).
F 13640 is a newly discovered high-efficacy 5-HT1A receptor agonist that produces exceptional analgesia in animal models of tonic and chronic, nociceptive and neuropathic pains by novel molecular and neuroadaptive mechanisms. Here we examined the effects of F 13640 and remifentanil (0.63 mg/kg with either compound) when injected i.p. either before or 15 min after rats underwent orthopedic surgery. Surgery consisted of the drilling of a hole in the calcaneus bone and of an incision of the skin, fascia and plantar muscle of one foot. During surgery, the concentration of volatile isoflurane was progressively incremented depending on the animal's response to surgical maneuvers. Other experiments examined the dose-dependent effects of F 13640 (0.04 to 0.63 mg/kg) on surgical pain as well as on the Minimum Alveolar Concentration of isoflurane. Both F 13640 and remifentanil markedly reduced the intra-operative isoflurane requirement. F 13640 also reduced measures of postoperative pain (i.e., paw elevation and flexion). With these postoperative measures, remifentanil produced short-lived analgesia followed by hyperalgesia. F 13640 significantly reduced both surgical pain and the isoflurane Minimum Alveolar Concentration from 0.16 mg/kg onward. F 13640 produced powerful intra- and postoperative analgesia in rats undergoing orthopedic surgery. Unlike the opioid, remifentanil, F 13640 caused no hyperalgesia with ongoing postoperative pain, and should remain effective with protracted postoperative use.
Keywords: Serotonin; 5-HT1A receptor; Orthopedic surgery; Intra-operative pain; Postoperative pain; Opioid hyperalgesia;
Local effects of acute ethanol on dopamine neurotransmission in the ventral striatum in C57BL/6 mice by Evgeny A. Budygin; Tiffany A. Mathews; Gennady B. Lapa; Sara R. Jones (40-45).
In this study, fast-scan cyclic voltammetry in brain slices was used to evaluate the effects of acute ethanol on dopamine terminal release and uptake in the nucleus accumbens of C57BL/6 mice. We found that pharmacologically relevant concentrations of ethanol (20 and 100 mM) did not alter electrically evoked dopamine release, while the highest concentration (200 mM) significantly decreased release (∼45%). No significant changes were observed in the rate of dopamine uptake after ethanol (20, 100 or 200 mM). In addition, it was established that a moderate dose (2 g/kg, i.p.) of ethanol did not alter the rate of dopamine synthesis, measured as L-dihydroxyphenylalanine (L-DOPA) accumulation. However, a high dose (5 g/kg, i.p.) of ethanol significantly increased the levels of L-DOPA to 60% above the control value. These data are consistent with earlier findings obtained in brain slices from rats; dopamine release, but not clearance, is affected by acute ethanol.
Keywords: Dopamine; Ethanol; C57BL/6 mouse; Nucleus accumbens; Voltammetry;
Analgesic properties of the novel compound M43068 in rat models of acute and neuropathic pain by Yasushige Akada; Reiko Mori; Yutaka Kato; Fumiaki Yamasaki; Hidenori Mochizuki (46-53).
We investigated the effects of 2-(4-hydroxybenzoyl)amino-2-methylpropionic acid (M43068), a novel analgesic agent, in rat models of acute and neuropathic pain. Oral M43068 (10–100 mg/kg) suppressed only the late phase of formalin-induced nociceptive behaviors. In the neuropathic pain model, oral M43068 (10–100 mg/kg) suppressed mechanical allodynia in the nerve-injured paw without affecting normal thresholds. On the other hand, i.v. M43068 (30 mg/kg) mainly suppressed the Aβ-fiber-mediated response with the Neurometer. I.c.v. pretreatment with the α1-adrenoceptor antagonist, prazosin, or i.p. pretreatment with the γ-aminobutyric acid (GABA)B receptor antagonist, saclofen, abolished the M43068-induced antinociception. However, oral M43068 (30–300 mg/kg) had no influence on blood pressure and motor function, unlike the α1-adrenoceptor and the GABAB receptor agonists. These data indicate that M43068 shows antinociceptive and anti-allodynic effects with reduced risks of side effects. It is suggested that the descending noradrenergic system is involved in the analgesic effects of M43068.
Keywords: Neuropathic pain; Allodynia; Formalin test; Antinociception; Neurometer; (Rat);
Dose- and duration-dependent effects of betahistine dihydrochloride treatment on histamine turnover in the cat by Brahim Tighilet; Suzanne Trottier; Michel Lacour (54-63).
Drugs interacting with the histaminergic system are currently used for vertigo treatment and it was shown in animal models that structural analogues of histamine like betahistine improved the recovery process after vestibular lesion. This study was aimed at determining the possible dose and duration effects of betahistine treatment on histamine turnover in normal adult cats, as judged by the level of messenger RNA for histidine decarboxylase (enzyme synthesizing histamine) in the tuberomammillary nuclei. Experiments were conducted on betahistine-treated cats receiving daily doses of 2, 5, 10, or 50 mg/kg during 1 week, 3 weeks, 2 months, or 3 months. The 1-week, 3-week, and 2- and 3-month treatments correspond to the acute, compensatory, and sustained compensatory stages of vestibular compensation, respectively. The lowest dose (2 mg/kg) given the longest time (3 months) was close to the dosage for vestibular defective patients. Data from the experimental groups were compared to control, untreated cats and to placebo-treated animals.The results clearly show that betahistine dihydrochloride administered orally in the normal cat interferes with histamine turnover by increasing the basal expression level of histidine decarboxylase mRNA of neurons located in the tuberomammillary nuclei of the posterior hypothalamus. The effects were both dose- and time-dependent.In conclusion, compensation of both static and dynamic deficits is subtended by long-term adaptive mechanisms that could be facilitated pharmacologically using betahistine dihydrochloride.
Keywords: Histidine decarboxylase; In situ hybridization; Betahistine dihydrochloride; Tuberomammillary nuclei; (Cat);
Individual differences in the sensitivity of cold allodynia to phentolamine in neuropathic rats by Sun Kwang Kim; Byung-Il Min; Ji Hoon Kim; Byung Gil Hwang; Gi Yong Yoo; Dong Suk Park; Heung Sik Na (64-66).
In neuropathic rats sensitive to phentolamine (α-adrenoreceptor antagonist, 2 mg/kg, i.p.), prazosin (α1-adrenoreceptor antagonist, 0.5 mg/kg, i.p.) significantly attenuated cold allodynia whereas yohimbine (α2-adrenoreceptor antagonist, 0.5 mg/kg, i.p.) had no significant effect. In neuropathic rats insensitive to phentolamine, yohimbine significantly exacerbated cold allodynia whereas prazosin had no significant effect. These results suggest that the individual differences in the sensitivity of cold allodynia to phentolamine may be due to the difference in the α-adrenoreceptor subtype predominantly involved in cold allodynia.
Keywords: Neuropathic pain; Cold allodynia; Phentolamine; Prazosin; Yohimbine; α-adrenoreceptor;
Differential G-protein coupling to GABAB receptor in limbic areas of alcohol-preferring and -nonpreferring rats by M. Paola Castelli; Fabio Pibiri; A. Paola Piras; Giovanni Carboni; Alessandro Orrù; Gian Luigi Gessa; Mauro A.M. Carai; Giancarlo Colombo (67-70).
The function of the γ-aminobutyric acidB (GABAB) receptor, measured as baclofen-stimulated [35S]GTPγS binding, was evaluated in some brain regions of Sardinian alcohol-preferring (sP) and -nonpreferring (sNP) rats. EC50 value of baclofen-stimulated [35S]GTPγS in limbic areas was approximately 125% higher in alcohol-naive sP than sNP rats; voluntarily consumed alcohol reduced the EC50 value to a level similar to that of alcohol-naive sNP rats. These results suggest the presence of a genetically determined lower function of the GABAB receptor in limbic areas of sP than sNP rats; this differential functioning of the GABAB receptor may contribute to the opposite preference for alcohol in these rat lines.
Keywords: GABAB receptor; [35S]GTPγS binding; voluntary alcohol consumption; (sP) Sardinian alcohol-preferring and (sNP) Sardinian alcohol-nonpreferring (Rat);
Influence of adenosine receptor agonists on benzodiazepine withdrawal signs in mice by Joanna Listos; Danuta Malec; Sylwia Fidecka (71-78).
The involvement of adenosine receptor agonists in benzodiazepine withdrawal signs was evaluated as the seizure susceptibility of mice. The concomitant administration of subthreshold dose of pentetrazole (55.0 or 60.0 mg/kg, s.c.) with flumazenil (10.0 mg/kg, i.p.) in mice chronically treated with temazepam or diazepam induced the appearance of withdrawal signs: clonic seizures, tonic convulsions and death episodes. The administration of the selective A1 (CPA-N 6-cyclopentyladenosine), A2A (CGS 21680-2-p-(2-carboxyethyl)phenethylamino-5′-N-ethylcarboxamidoadenosine hydrochloride) and the non-selective A1/A2A (NECA-5′-N-ethylcarboxamidoadenosine) adenosine receptor agonists (i.p.) evoked the significant attenuation of benzodiazepine withdrawal signs, and these effects were more expressed in temazepam- than in diazepam-dependent mice. CPA has shown the most apparent and dose-dependent attenuating effect. The results confirm that adenosine A1 and A2A receptors are involved in benzodiazepine withdrawal signs, and adenosine A1 receptor plays a predominant role in this phenomenon.
Keywords: Temazepam; Diazepam; Withdrawal sign; Adenosine agonist;
Dexmedetomidine selectively suppresses dominant behaviour in aggressive and sociable mice by Martin Votava; Ladislav Hess; Jiří Slíva; Miloslav Kršiak; Viktoria Agová (79-85).
Dexmedetomidine is a highly specific α2-adrenoreceptor agonist, which is now clinically used to induce sedation in patients in the intensive care units. Behavioural effects of dexmedetomidine have been little studied so far. The drug was reported to reduce behaviour such as locomotion or measures of anxiety or aggression in animals. The aim of the present study was to ascertain whether dexmedetomidine inhibits behaviour uniformly or with respect to particular stimuli or situations. Therefore, behavioural effects of dexmedetomidine were studied in the social conflict test in male mice (after three weeks of individual housing), which provides a wide spectrum of behavioural activities in two types of animals (aggressive and sociable mice) as well as in the activity cage. Dexmedetomidine (5–40 μg/kg i.p.) decreased locomotion in the activity cage and this effect was fully antagonized by atipamezole, a selective α2-adrenereceptor antagonist. However, dexmedetomidine did not reduce locomotion during social conflict. The only significant effects during social conflict were a selective and dose-dependent antiaggressive effect in aggressive mice and a selective reduction of social investigation (‘sociability’) in sociable mice. Thus, dexmedetomidine appears to inhibit predominantly dominant behaviour evoked by biologically important stimuli. The ability of dexmedetomidine to reduce aggression might be utilized for treatment of aggressive states. Sedation caused by dexmedetomidine can be easily disrupted and thus the drug may have an advantage over benzodiazepines or neuroleptics, which are used in this indication.
Keywords: Dexmedetomidine; Atipamezole; Animal behaviour; Social conflict; Aggression;
Effect of 17-β-estradiol administration during adriamycin-induced cardiomyopathy in ovariectomized rat by Juan R. Muñoz-Castañeda; Pedro Montilla; Maria C. Muñoz; Inmaculada Bujalance; Jordi Muntané; Isaac Túnez (86-92).
The incidence of cardiovascular diseases in humans differs in relation to the age of the patient. Although women suffer less than men from cardiovascular disorders during 15–55 years, after this period the incidence is equivalent in both sexes. This data suggests a cytoprotective effect of estrogens against cardiovascular disease. The estrogens, especially 17-β-estradiol, are important antioxidant molecules with potential cytoprotective properties during oxidant/antioxidant disbalance induced by oxidative stress. Oxidative stress is often the underlying mechanism during vascular alterations and cardiac damage.The present study evaluated the role of ovariectomy and/or 17-β-estradiol administration on antioxidant status and lipid peroxidation during cardiac injury induced by adriamycin. Different parameters were measured, including hemodynamic response (arterial pressure and cardiac frequency), lipid peroxidation products (malondialdehyde), protein carbonylation, antioxidant status (reduced glutathione, glutathione peroxidase, superoxide dismutase and catalase), and cardiac injury (creatinine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase).Our study showed that 17-β-estradiol reduced all of the parameters related to oxidative stress and cardiac injury in ovariectomized rats treated with adriamycin.
Keywords: 17-β-estradiol; Cardiomyopathy; Oxidative stress; Ovariectomy; Adriamycin;
Contribution of endogenous opioids and nitric oxide to papillary muscle contractile impairment in cholestatic rats by Farzad Ebrahimi; Sina Tavakoli; Amir Reza Hajrasouliha; Hamed Shafaroodi; Hamed Sadeghipour; Kiarash Riazi; Amir Ali Borhani; Golbahar Houshmand; Seyed Hossein Ahmadi; Ahmad Reza Dehpour (93-100).
Attenuated responsiveness to adrenoceptor stimulation has been proposed as an important factor underlying cardiovascular complications of cholestasis. We examined isolated papillary muscle responsiveness to α (phenylephrine) and β-adrenoceptor (isoproterenol) agonists in 7-day bile duct-ligated rats. We investigated the role of nitric oxide (NO) and endogenous opioids in papillary muscle hyporesponsiveness to isoproterenol stimulation. In order to evaluate the effect of NO and endogenous opioids, animals were treated with chronic subcutaneous injections of N (ω)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg/day) or naltrexone (20 mg/kg/day), or isolated papillary muscles were exposed acutely to the same drugs (10− 4 and 10− 6 M, respectively) in an organ bath. The basal contractile force of papillary muscle, + dT / dt max and − dT / dt max, was significantly decreased in bile duct-ligated rats compared to sham-operated ones (P < 0.05, for each value). The concentration–response curve for phenylephrine and isoproterenol demonstrated a reduced maximum effect in bile duct-ligated rats compared to the sham-operated group (P < 0.01 and 0.05, respectively). Basal contractile abnormalities of bile duct-ligated rats were corrected by L-NAME or naltrexone treatment, either acute or chronic. While chronic L-NAME treatment resulted in a left-ward shift (P < 0.05), it had no effect on the maximum effect in bile duct-ligated rats. Acute L-NAME treatment did not influence isoproterenol responsiveness. Acute and chronic naltrexone treatment resulted in partial and complete correction of the hyporesponsiveness of bile duct-ligated rats, respectively (P < 0.05). This investigation demonstrates that the papillary muscles of 7-day bile duct ligated-rats have an impaired basal contractility and hyporesponsiveness to both α and β-adrenoceptor stimulation. It also provides evidence for the involvement of increased opioidergic tone and NO overproduction in cholestasis-induced cardiac impairment.
Keywords: Adrenoceptor; Cardiomyopathy; Cholestasis; Endogenous opioid peptide; NO (Nitric oxide); Papillary muscle;
Effects of KR-32570, a new sodium hydrogen exchanger inhibitor, on myocardial infarction and arrhythmias induced by ischemia and reperfusion by Byung Ho Lee; Kyu Yang Yi; Sunkyung Lee; Sunghou Lee; Sung-eun Yoo (101-108).
The present study was performed to evaluate the cardioprotective effects of [5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl]guanidine (KR-32570) in rat and dog models of coronary artery occlusion and reperfusion. In addition, we sought to clarify the efficacy of KR-32570 on reperfusion-induced fatal ventricular arrhythmia. In anesthetized rats subjected to 45-min coronary occlusion and 90-min reperfusion, KR-32570 (i.v. bolus) dose-dependently reduced myocardial infarct size from 58.0% to 50.7%, 35.3%, 33.5% and 27.0% for 0.03, 0.1, 0.3 and 1.0 mg/kg, respectively (P < 0.05). In anesthetized beagle dogs that underwent 1.2-h occlusion followed by 3.0-h reperfusion, KR-32570 (3 mg/kg, i.v. bolus) markedly decreased infarct size from 28.9% in vehicle-treated group to 8.0% (P < 0.05), and reduced the reperfusion-induced release in creatine kinase isoenzyme MB, lactate dehydrogenase, Troponin-I and glutamic-oxaloacetic transaminase. KR-32570 dose-dependently decreased the incidence of premature ventricular contraction, ventricular tachycardia or ventricular fibrillation induced by ischemia and reperfusion in rats. Similar results were obtained in dogs with reperfusion-induced arrhythmia. In separate experiments to assess the effects of timing of treatment, KR-32570 given 10 min before or at reperfusion in rat models also significantly reduced the myocardial infarct size (40.9% and 46.1%, respectively) compared with vehicle-treated group. In all studies, KR-32570 caused no significant changes in any hemodynamic profiles. Taken together, these results indicate that KR-32570 significantly reduced the myocardial infarction and incidence of arrhythmias induced by ischemia and reperfusion in rats and dogs, without affecting hemodynamic profiles. Thus, it could be potentially useful in the prevention and treatment of myocardial injuries and lethal ventricular arrhythmias.
Keywords: KR-32570; Cardioprotection; Antiarrhythmia; Na+/H+ exchanger;
Characterization of KATP-channels in rat basilar and middle cerebral arteries: Studies of vasomotor responses and mRNA expression by Inger Jansen-Olesen; Camilla Holbech Mortensen; Najat El-Bariaki; Kenneth Beri Ploug (109-118).
Changes in the activity of K+ channels represent a major mechanism that regulates vascular tone. Cerebrovascular adenosine 5′-triphosphate-sensitive K+(KATP) channels were characterized in studies of the molecular expression and vasomotor reactivity to different KATP channel openers in rat basilar and middle cerebral arteries. Both arteries showed strong mRNA expression of the subunits of the pore-forming inward-rectifying K+ channel type 6.1 (Kir6.1), Kir6.2 and the connected sulfonylurea receptor (SUR) subunits, SUR1 and SUR2B, while only weak bands for SUR2A were seen. The KATP channel openers induced relaxation of prostaglalndin F2α-precontracted isolated basilar and middle cerebral arteries with the order of potency N-Cyano-N-(1,1-dimethylpropyl)-N″-3pyridylguanidine (P-1075) > levcromakalim > N-(4-Phenylsulfonylphenyl)-3,3,3-trifluoro-2-hydroxy-2-methylpropanamide (ZM226600) > pinacidil > diazoxide. The responses induced by levcromakalim, ZM226600 and diazoxide were significantly more potent in basilar arteries than in middle cerebral arteries, while pinacidil and P-1075 were equipotent. Endothelium removal decreased (P < 0.05) the sensitivity (pIC50) of basilar arteries, but not of middle cerebral arteries, to pinacidil, levcromakalim, P-1075 and ZM226600. The maximum relaxant response to P-1075 was stronger (P < 0.005) in basilar arteries with endothelium than without endothelium. Correlation of the relaxant potency of KATP channel openers in rat basilar and middle cerebral arteries with historical measurements of affinity obtained in COS-7 cell lines expressing either SUR1, SUR2A or SUR2B showed that vasodilatation by KATP channel openers correlated with binding to either the SUR2A or the SUR2B subunit. Glibenclamide was a blocker of relaxation induced by pinacidil, levcromakalim, P-1075 and ZM226600 in basilar arteries. Only a weak antagonistic effect of glibenclamide on pinacidil-, levcromakalim- and ZM226600-induced relaxations was found in middle cerebral arteries. The subunit profile and the observed pharmacological properties suggest that the KATP channels expressed in rat basilar and middle cerebral artery are likely to be composed of SUR2B co-associated with Kir6.1 or Kir6.2. In basilar arteries, but not in middle cerebral arteries, endothelial KATP channels may be involved.
Keywords: ATP-sensitive K+ channels (Adenosine 5′-triphosphate-sensitive K+channels); Cerebral artery; Vasodilatation; Endothelium; Vascular smooth muscle; (Rat);
Role of prostaglandins in urotensin II-induced vasodilatation in the coronary arteries of aged rats by Akira Ishihata; Tomoko Ogaki; Tomomi Aita; Yumi Katano (119-126).
Endothelial function is modulated by aging. The objective of this study was to elucidate whether aging influences urotensin II-induced coronary vasodilatation, and whether aging influences the production of endothelial factors in response to urotensin II. We examined the effects of urotensin II on coronary flow in Langendorff-perfused rat hearts. The production of nitric oxide (NO), prostacyclin and prostaglandin (PG)E2 were determined in the coronary effluent of both young and aged rats. Urotensin II increased coronary flow in Langendorff-perfused hearts in both young and aged rats and vasodilation did not differ between young and aged rats. Pretreatment with a NO synthase inhibitor, N G-nitro-l-arginine (l-NNA), significantly inhibited urotensin II-induced vasodilatation in young rats, but not in aged rats. In addition, urotensin II increased the production of NO only in young rats. On the other hand, the cyclooxygenase inhibitor diclofenac significantly attenuated the urotensin II-induced coronary vasodilatation in both young and aged rats. Urotensin II markedly increased the release of the vasodilating prostacyclin and PGE2 into the coronary effluent. Production of these prostanoids was maintained even in the aged coronary arteries. These results indicate that the production of NO in the endothelium of coronary arteries is impaired in aged rats, and that prostacyclin and PGE2 may play an important role in regulating urotensin II-induced coronary vasodilatation.
Keywords: Aging; Vasoactive agent; Coronary circulation; Endothelial function; Nitric oxide; Prostaglandin;
The role of NF-κB signaling in impaired liver tissue repair in thioacetamide-treated type 1 diabetic rats by Sachin S. Devi; Harihara M. Mehendale (127-136).
Previously we reported that an ordinarily nonlethal dose of thioacetamide (300 mg/kg) causes liver failure and 90% mortality in type 1 diabetic rats, primarily because of inhibited tissue repair. On the other hand, the diabetic rats receiving 30 mg thioacetamide/kg exhibited equal initial liver injury and delayed tissue repair compared to nondiabetic rats receiving 300 mg thioacetamide/kg, resulting in a delay in recovery from that liver injury and survival. These data indicate that impaired tissue repair in diabetes is a dose-dependent function of diabetes. The objective of the present study was to test the hypothesis that disrupted nuclear factor-κB (NF-κB)-regulated cyclin D1 signaling may explain dose-dependent impaired tissue repair in the thioacetamide-treated diabetic rats. Administration of 300 mg thioacetamide/kg to nondiabetic rats led to sustained NF-κB-regulated cyclin D1 signaling, explaining prompt compensatory tissue repair and survival. For the first time, we report that NF-κB–DNA binding is dependent on the dose of thioacetamide in the liver tissue of the diabetic rats. Administration of 300 mg thioacetamide/kg to diabetic rats inhibited NF-κB-regulated cyclin D1 signaling, explaining inhibited tissue repair, liver failure and death, whereas remarkably higher NF-κB–DNA binding but transient down regulation of cyclin D1 expression explains delayed tissue repair in the diabetic rats receiving 30 mg thioacetamide/kg. These data suggest that dose-dependent NF-κB-regulated cyclin D1 signaling explains inhibited versus delayed tissue repair observed in the diabetic rats receiving 300 and 30 mg thioacetamide/kg, respectively.
Keywords: Diabetes; Liver; NF-κB; Thioacetamide; Tissue repair;
Therapeutic administration of Y-40138, a multiple cytokine modulator, inhibits concanavalin A-induced hepatitis in mice by Tetsuko Fukuda; Akira Mogami; Masao Hisadome; Hirotsugu Komatsu (137-142).
Concanavalin A-induced hepatitis is often used as a model of liver injury. In this model, plasma tumor necrosis factor-α (TNF-α) level increased in concanavalin A-injected mice. Prophylactic treatment with Y-40138, N-[1-(4-[4-(pyrimidin-2-yl)piperazin-1-yl]methyl phenyl)cyclopropyl] acetamide·HCl, significantly suppressed the increase in plasma TNF-α level. In this study, we compared the effect of Y-40138 with those of pentoxifylline and anti-TNF-α antibody on concanavalin A-induced hepatitis. Prophylactic treatment with pentoxifylline, anti-TNF-α antibody and Y-40138 reduced plasma alanine aminotransferase level. Therapeutic treatment with Y-40138 significantly reduced plasma alanine aminotransferase level, but pentoxifylline and anti-TNF-α antibody did not. Therapeutic treatment with Y-40138 significantly reduced plasma interferon-γ (IFN-γ) and monokine induced by interferon-γ levels. From these results, Y-40138 may be expected as a new class of therapeutic drug for treatment of TNF-α, IFN-γ and/or chemokine-related liver diseases such as alcoholic liver disease.
Keywords: Y-40138; TNF-α; IFN-γ; IL-4; Chemokine; Pentoxifylline; Anti-TNF-α antibody; Concanavalin A; Hepatitis;
Antagonistic effects of novel non-peptide chlorobenzhydryl piperazine compounds on contractile response to bradykinin in the guinea-pig ileum by Yoo Lim Kam; Jai Youl Ro; Hwa-Jung Kim; Hea-Young Park Choo (143-150).
Two novel compounds, N-phenylacetyl-N′-(4-methoxybenzyl)-N″-1-(4-chlorobenzhydryl)piperazine iminodiacetic acid triamide (compound I) and N-phenylacetyl-N′-(4-methylbenzyl)-N″-1-(4-chlorobenzhydryl)piperazine iminodiacetic acid triamide (compound II), designed and synthesized as novel non-peptide bradykinin B2 receptor antagonists, were studied for their functional activities in isolated guinea-pig ileum smooth muscle. These compounds were compared with the conventional peptide bradykinin B2 receptor antagonist, icatibant (H–dArg-Arg-Pro-Hyp-Gly-Thi-Ser-dTic-Oic-Arg–OH) for their in vitro functional activities. Compounds I and II showed highly potent, time-dependent insurmountable antagonism against contractile responses to bradykinin (pK B 8.80 and 8.57, respectively) with progressive reduction of maximum effect maintaining the concentration producing half maximal-response unchanged. Otherwise, icatibant, known as a non-competitive antagonist, showed a rightward displacement of cumulative concentration–response curves to bradykinin with decrease of its maximum effect (pK B 8.73). The IC50 values of compounds I and II were 3.56 × 10− 8 and 6.30 × 10− 8 M, respectively, while that of icatibant was 5.02 × 10− 8 M. The profile of action of compounds I and II varied when contact time was prolonged from 5 to 60 min, whereas that of icatibant did not. The inhibitory effects of the newly synthesized compounds and icatibant on the contractile response to bradykinin were differently reverted by washout (icatibant < 100 min, compounds I and II > 100 min). This class of compounds containing the chlorobenzhydryl piperazine moiety is expected to be a novel non-peptide bradykinin B2 receptor antagonists.
Keywords: Bradykinin receptor antagonist; Non-peptide; Guinea-pig ileum smooth muscle contraction; Chlorobenzhydryl piperazine;
Therapeutic efficacy of ozone in patients with diabetic foot by Gregorio Martínez-Sánchez; Saied M. Al-Dalain; Silvia Menéndez; Lamberto Re; Attilia Giuliani; Eduardo Candelario-Jalil; Hector Álvarez; José Ignacio Fernández-Montequín; Olga Sonia León (151-161).
Oxidative stress is suggested to have an important role in the development of complications in diabetes. Because ozone therapy can activate the antioxidant system, influencing the level of glycemia and some markers of endothelial cell damage, the aim of this study was to investigate the therapeutic efficacy of ozone in the treatment of patients with type 2 diabetes and diabetic feet and to compare ozone with antibiotic therapy. A randomized controlled clinical trial was performed with 101 patients divided into two groups: one (n = 52) treated with ozone (local and rectal insufflation of the gas) and the other (n = 49) treated with topical and systemic antibiotics. The efficacy of the treatments was evaluated by comparing the glycemic index, the area and perimeter of the lesions and biochemical markers of oxidative stress and endothelial damage in both groups after 20 days of treatment. Ozone treatment improved glycemic control, prevented oxidative stress, normalized levels of organic peroxides, and activated superoxide dismutase. The pharmacodynamic effect of ozone in the treatment of patients with neuroinfectious diabetic foot can be ascribed to the possibility of it being a superoxide scavenger. Superoxide is considered a link between the four metabolic routes associated with diabetes pathology and its complications. Furthermore, the healing of the lesions improved, resulting in fewer amputations than in control group. There were no side effects. These results show that medical ozone treatment could be an alternative therapy in the treatment of diabetes and its complications.
Keywords: Ozone; Diabetes (and its complications); Diabetic foot; Oxidative stress; Antioxidant defense system;
Author Index (162-163).
Keyword Index (164-167).