The Warsaw High Preferring (WHP) and Warsaw Low Preferring (WLP) lines were bred from Wistar foundation stock to obtain lines of rats that differ in their preference for ethanol (EtOH) solutions. The WHP line has met major criteria for an animal model of alcoholism. The WHP rats voluntarily drink excessive amounts of alcohol while the WLP rats consume negligible amounts of alcohol. These patterns of EtOH consumption are stable in time and independent of the manner of access to EtOH solutions. Notably, when exposed to the increasing EtOH concentrations both WHP and unselected Wistar rats gradually increased total EtOH intake. In contrast, WLP rats when exposed to the increasing concentrations of EtOH consumed almost negligible amounts of EtOH. Furthermore, the WHP rats show an increased responsiveness to the stimulatory effects of low dose of EtOH.
The present study was focused on evaluation of locomotor cross-sensitization between nicotine and ethanol in mice. First, we demonstrated that, after 5 daily injections, nicotine (0.5 mg/kg, ip) produced sensitization to its own locomotor stimulant effect. Moreover, nicotine-experienced mice manifested an enhanced response to ethanol challenge (2 g/kg, ip) indicating the development of cross-sensitization between nicotine and ethanol in mice. Additionally, the L-type voltage-dependent calcium channel antagonists: verapamil and diltiazem, but not nimodipine, at the dose of 20 mg/kg, injected before the ethanol challenge, blocked the expression of this cross-sensitization. These findings support the hypothesis that similar neural calcium-dependent mechanisms are involved in the sensitization to locomotor stimulant effects of nicotine and ethanol and point to certain differences in acute behavioral effects of various classes of calcium channel inhibitors.
The aim of the study was to determine the effect of the often applied drugs in cardiovascular diseases (metoprolol, acetylsalicylic acid, simvastatin and molsidomine) on antioxidative/oxidative balance in vivo. The determination of oxidative status was based on measurements of concentration of: thiobarbituric acid reactive substances (TBARS - lipid peroxidation products), protein carbonyl groups (marker of proteins oxidative injury), nitrotyrosine (marker of NO-mediated tissue damage) and sulfhydryl groups (protein oxidation product). The assays were performed in the plasma and whole blood of rabbits after three weeks of daily intragastric administration of the drugs mentioned above. It was shown that all drugs except acetylsalicylic acid caused an increase in the plasma and hemolysate levels of TBARS. No changes in nitrotyrosine concentration were observed after drug administration. The content of carbonyl groups did not change after administration of metoprolol, but increased significantly after simvastatin and molsidomine administration. Blood sulfhydryl group concentration was not changed by metoprolol but it significantly decreased after acetylsalicylic acid and increased significantly after molsidomine administration.
The present study was designed to examine the effects of the donor of nitric oxide (NO), NaNO(2) and the inhibitor of NO synthase, N(omega)-nitro-L-arginine (L-NNA), on the development of dimethylnitrosamine (DMNA)-induced chronic hepatitis in rats. L-NNA decreased rat survival and enhanced the severity of hepatic encephalopathy in the DMNA-treated animals. The aggravation of the morphological signs of hepatitis, the activation of serum alanine aminotransferase and cytosolic superoxide dismutase activities and the increase in the liver malondialdehyde content were observed in this group. The treatment with NaNO(2) improved liver morphology, decreased serum marker enzyme activities, lowered the activities of alpha-D-mannosidase and N-acetyl-beta-D-glucosaminidase compared to the DMNA-treated group. The results of the morphological and biochemical studies suggest that L-NNA increased DMNA-induced liver damage, whereas NaNO(2) partially prevented the development of chronic hepatitis. It is proposed that the opposite effects of L-NNA and NaNO(2) are partially explained by a modulation of the free radical-dependent processes in the liver.
gamma-Hydroxybutyric acid (GHB) is a naturally occurring substance with function of an inhibitory neurotransmitter in the central nervous system in mammals. GHB can be used as a medicine in narcolepsy (Xyrem) and for general anesthesia (sodium oxybate). It is also a popular drug of abuse, causing coma, addiction and severe withdrawal syndrome, and, therefore, demanding thorough studies on the GHBergic system and expanded research on toxicology of this compound. The aim of this review is to present the proved and some suggested mechanisms of its action from pharmacological point of view, which may help to properly treat intoxication or other pathological states caused by GHB ingestion. Some new GHB derivatives studied for analogous action and their present use are also described.
Recently, we have shown that some HMG-CoA reductase inhibitors (statins) induce immediate pleiotropic effects in vascular endothelium both in vivo and in vitro, to mention only PGI2-mediated thrombolysis in rats and NO-mediated endothelium-dependent vasodilation in guinea pig coronary circulation. Here we look whether immediate endothelial effect of statins is associated with mobilization of intracellular calcium ions [Ca2+]i in cultured bovine aortic endothelial cells (BAEC). We analyzed the effects of various statins (atorvastatin, cerivastatin, simvastatin, lovastatin and pravastatin at concentration of 10-30 microM) on [Ca2+]i in BAEC in comparison to responses induced by bradykinin (Bk) (10 nM), adenosine diphosphate (1 microM), acetylcholine (100 nM), adrenaline (10 microM), serotonin (10 microM) or calcium ionophore A 23187 (0.1 microM) using FURA-2 according to fluorimetric method of Grynkiewicz et al. Basal [Ca2+]i level in BAEC was between 60 and 100 nM. Bk was the most potent to induce [Ca2+]i response. Delta[Ca2+]i induced by Bk was 331.9 +/- 19.49 nM (n = 36). Delta[Ca2+]i induced by statins (30 microM), i.e. atorvastatin, cerivastatin, simvastatin, lovastatin and pravastatin were 66.4 +/- 7.38% (n = 6), 54.8 +/- 10.12% (n = 5), 58.8 +/- 13.9% (n = 8), 27.7 +/- 7.19% (n = 5) and 0% (n = 5) of the response induced by Bk (10 nM), respectively. In summary, all statins tested, except pravastatin, induce immediate increase in [Ca2+]i in endothelium. This pleiotropic activity of statins in endothelium, most likely not related to the inhibition of HMG-CoA reductase, may represent an intracellular correlate for the immediate release of NO and PGI2 by these drugs that was reported by us previously.
The purpose of the present study was to identify the cellular processes and targets affected by treatment with bis-benzimidazole derivatives with chloroalkyl and bromoalkyl moieties (1-4) in the estrogen receptor-negative MDA-MB-231 human breast cancer cells. Treatment of the cells revealed that these compounds inhibited DNA synthesis and irreversibly inhibited the proliferative activity of the cells. All drugs 1-4 inhibited relaxation of pBR 322 DNA induced by both topoisomerases, although topoisomerase I was 2- to 9-fold more sensitive than topoisomerase II. This suggests that DNA-binding may be implicated in the cytotoxicity of bis-benzimidazole derivatives with alkylating moiety, possibly by inhibiting interactions between topoisomerases and their DNA targets.
The aim of the present study was to examine a potential anxiolytic- and antidepressant-like action of (+)-7-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (7-OH-DPAT), a preferential dopamine D(3) receptor agonist, and N-{4-[4-(2-methoxyphenyl)-1-piperazinyl]butyl}-2-naphthylcarboxamide (BP 897), a partial dopamine D(3) receptor agonist, in male Wistar rats. Diazepam or imipramine were used as reference compounds. The anxiolytic-like effect of those drugs was tested in the elevated plus-maze test. The antidepressant-like effect was estimated using the forced swimming test. The obtained results showed that 7-OH-DPAT at low doses and BP 897 (like diazepam) induced anxiolytic-like effects in the elevated plus-maze test. 7-OH-DPAT, BP 897 and diazepam, tested at the doses effective in the model of anxiolytic-like actions, did not affect motor coordination. Moreover, 7-OH-DPAT at higher doses, like imipramine, showed antidepressant-like effect, significantly reducing immobility time in the forced swimming test. Combined treatment with 7-OH-DPAT and imipramine induced a stronger effect in Porsolt's test than administration of either drug alone, but did not increase the locomotor activity. In contrast, BP 897 was inactive in the forced swimming test when given alone but it potentiated the antidepressant-like effect of imipramine. These data suggest that preferential D(3) receptor agonists may play a role in the therapy of anxiety and/or depression, however, further studies are necessary to elucidate the mechanism of these actions.
The purpose of the present study was to investigate the effects of competitive NMDA receptor antagonists,D,L-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CGP 37849) and its ethyl ester (CGP 39551), or agonist, N-methyl-D-aspartate (NMDA) on spontaneous alternation in mice exposed to cerebral oligemia. Alternation behavior was evaluated in an Y-maze. Transient cerebral oligemic hypoxia was induced by bilateral clamping of carotid arteries (BCCA) for 30 min under pentobarbital anesthesia. In BCCA mice, CGP 37849 (5 mg/kg, ip) impaired spontaneous alternation when given 48 h or 7 days after surgery. CGP 39551 (5 mg/kg, ip) had no effect.NMDA (50 mg/kg, sc) improved performance of the task in BCCA mice when tested 48 h after surgery. These results suggest that cerebral oligemic hypoxia induced by BCCA leads to functional disturbances in the central nervous system, such as spontaneous alternation impairment and increased susceptibility to NMDA receptor-related drugs. Adverse potential of cerebral oligemia may limit a therapeutic use of NMDA receptor antagonists.
Although there are no literature data, which would clearly describe the role of catecholaminergic systems (including dopaminergic system) in the expression of the liver cytochrome P-450, there are well documented reports on physiological regulation of cytochrome P-450 by endogenous hormones (glucocorticoids, sex hormones, thyroid hormones, growth hormone, insulin) and by the immune system (cytokines), and all these factors remain under central nervous system control. Therefore, one can expect that dysfunction of catecholaminergic systems may lead to significant changes in activities of particular cytochrome P-450 isoenzymes by altering levels of endogenous hormones. The mechanism underlying dopamine-induced regulation of the liver cytochrome P-450 expression seems not to be direct, but rather mediated by pituitary hormones and cytokines.
Neuroleptics penetrate into the brain, where they act not only on neurons but probably also on glial cells. In the available literature, there are no reports on the effect of neuroleptics on cytokine release in glia cultures. The aim of this study was to evaluate the effect of neuroleptics on the release of proinflammatory cytokines (IL-1beta and IL-2) by mixed glial and microglial cell cultures. Trifluperidol at 20 and 2 muM reduced IL-beta secretion by mixed glial cultures after 3 days of exposure. Trifluperidol at 20, 2 and 0.2 muM diminished IL-beta secretion after 1 day of incubation. Trifluperidol at 20 and 2 muM reduced IL-2 release after 1 and 3 days of exposure. Flupentixol at 20 and 2 muM reduced IL-1beta by mixed glial cell cultures after 3 days of exposure. Flupentixol at 20, 2 and 0.2 muM caused diminution of IL-1beta release after 1 day of exposure. Flupentixol at 20 and 2 muM reduced IL-2 release after 1 day of incubation. Flupentixol at 20, 2 and 0.2 muM diminished IL-2 release after 3 days of exposure. Flupentixol at 20, 10, 2 and 0.2 muM reduced IL-1beta release by microgial cell cultures. Flupentixol at 20, 10 and 2 muM reduced release of IL-2 by microglial cells after 1 day of exposure. The results of the present study suggest that neuroleptics have an inhibiting effect on the release of glial cytokines, but clinical significance this results remains to be elucidated.
The oxidative stress status of the transfusion-dependent Ebeta- and beta-thalassemia patients were studied before and after treatment with vitamin E for a period of four weeks. The level of cellular vitamin antioxidants viz. ascorbic acid and vitamin E in the thalassemia patients were found to be considerably lower compared to normal subjects. The activities of enzymatic antioxidants viz. catalase, glutathione peroxidase and glutathione reductase were found to be drastically reduced in untreated Ebeta- and beta-thalassemic patients when compared to normal subjects. However, the activity of superoxide dis-mutase was found to be increased in both types of untreated thalassemic patients when compared to normal individuals. An increase in superoxide dismutase and a decrease in catalase activity reflects the presence of a severe oxidative stress situation in the erythrocytes of the untreated transfusion dependent Ebeta- and beta-thalassemia patients. Changes in erythrocyte membrane protein pattern in untreated Ebeta- and beta-thalassemia patients when compared to normal erythrocyte further confirm the presence of continued oxidative stress in the ailing thalassemic erythrocytes. All these changes in the antioxidant status as well as the changes in the erythrocyte membrane proteins are ameliorated to considerable extent when the transfusion-dependent Ebeta- and beta-thalassemia patients were treated with vitamin E at a dose of 10 mg/kg/day for a period of four weeks. The patients during the treatment period did not exhibit any side effects and gained in body weight indicating a healthy status. The present study reveals that the lipophilic antioxidant vitamin E could be useful in the management of transfusion-dependant Ebeta- and beta-thalassemia patients.
Angiotensin converting enzyme inhibitors (ACE-Is) are the main drugs used in the treatment of essential hypertension and congestive heart failure in adults. Recently, we have demonstrated the antithrombotic effect of captopril (CAP) and enalapril (ENA) in venous thrombosis model in adult rats. One might also suggest the beneficial effect of those drugs on hemostasis in young individuals. Two months old male Wistar rats were used in the study. Acute administration of CAP at a dose of 50 and 100 mg kg(-1) significantly reduced the venous thrombus weight. Dose-dependent reduction in the thrombus weight was also observed in ENA (3, 10, 30 mg kg(-1))-treated rats. Strong reduction in the thrombus weight was also seen after chronic administration of CAP (2 x 25 mg kg(-1)) and ENA (1 x 15 mg kg(-1)). Both drugs given chronically reduced the frequency of thrombi. Systolic blood pressure was reduced to similar extent after acute and chronic application of the drugs. CAP shortened euglobulin clot lysis time (ECLT) when given acutely (100 mg kg(-1)) and chronically (2 x 25 mg kg(-1)). ENA decreased ECLT only when given at multiple doses (1 x 15 mg kg(-1)). None of the drugs changed prothrombin time or activated partial tromboplastin time. We conclude that CAP and ENA possess antithrombotic effect in young individuals. Activation of the fibrinolytic pathway seems to play an important role in the mechanism of their antithrombotic action.
The ideal antiepileptic drug (AED) should correct the aberrant pathophysiology of epileptogenesis without interfering with normal neurotransmission A new group of drugs with antiepileptic efficacy, without sedative properties, would be an exciting prospect. Theoretical considerations and results from experimental animal models of epilepsy have put forward the possibility that calcium (Ca2+) antagonists may form such a group. The initiation of epileptogenic activity in the neuron is thought to be connected with the phenomenon known as "intrinsic burst firing", which is activated by an inward Ca2+ current. Ca2+ is described as the primary mediator of "excitotoxic" neuronal damage. Both necrotic and apoptotic cell death is associated with Ca2+ entry into the cells during status epilepticus. The Ca2+ channel blockers depressed epileptic depolarizations of neurons. In this review, we present anticonvulsant effects of cinnarizine, flunarizine, nifedipine, nimodipine, nicardipine, amlodipine, isradipine, niguldipine, diltiazem, verapamil and dantrolene in animal models of seizures. Also, a detailed analysis of interactions between Ca2+ blockers and AEDs was performed. Clinical trials in intractable epilepsy support to a certain degree antiepileptic properties of Ca2+ antagonists.
Glucocorticoids are expressed in the central nervous system. Radioligand binding studies have shown their presence in the neurons of the limbic system, a structure involved in mood control and subtle regulation of hypothalamic-pituitary-adrenal (HPA) axis. Structures of the limbic system are also rich in dopaminergic innervation. It has been hypothesized that glucocorticoids may be important in causing and perpetuating depression. Our previous study has demonstrated that dexamethasone decreases the locomotor activity of mice and counteracts the hyperactivity induced by agonists of dopamine receptors. The aim of the present study was to find the possible mechanism responsible for these behavioral effects of dexamethasone. So we sought to examine the influence of chronic dexamethasone treatment on selective radioligand binding to dopamine D(1) ([(3)H]SCH 23390) and D(2) ([(3)H]spiperone) receptors in the brain of mice. The male Albino Swiss mice received dexamethasone (4, 8 or 16 mg/kg/day) for 14 days. The striatum and limbic system structures were isolated and the binding procedure was performed 3.5 or 48 h after the last injection. It was shown that 3.5 h after the last dose of dexamethasone (4 mg/kg/day), specific D(2) receptor binding was statistically significantly increased (by 64%) in the limbic system. On the contrary, the tendency to the reduction of specific D(2) receptor binding was observed in the striatum. Dexamethasone treatment did not influence the specific binding to D(1) receptors in any structure of the brain.
Neurogenesis is a process that involves cell proliferation, migration and differentiation. Adult neurogenesis has been discovered by Altman in the mid 1960s. It is known now that neurogenesis occurs in two main neurogenic areas of the adult mammalian brain: the olfactory bulb and the hippocampal dentate gyrus, although other brain regions, such as cortex or substantia nigra cannot be excluded. The rate of neurogenesis can be regulated in a positive and negative manner by several factors like, age, growth factors, hormones, environmental or pharmacological stimuli. Functional significance of adult neurogenesis is still under investigation, however, several evidences suggest involvement of newly generated neurons in cognitive processes. There are also several findings indicating that the impairment of adult neurogenesis may be involved in the pathophysiology of some brain diseases, like depression, epilepsy, ischemia or neurodegenerative disorders. It appears that alterations in the rate of neurogenesis may have important functional and therapeutic implications.
The inflammatory response is decreased in diabetic animals. After adrenals removal this impaired response in type 2 diabetic rats evaluated by pleurisy and vascular permeability tests was restored. Our studies demonstrate that endogenous corticosteroids play a partial role in the impaired inflammatory response in type 2 streptozotocin diabetic rats.
It is known that digoxin, which is a liposoluble cardiac glycoside, is well absorbed from intestine. In the present study, the absorption rates of digoxin from rat duodenum and the proximal and terminal parts of small intestine were determined in vitro. The isolated everted duodenum and intestinal sacs were put into oxygenated Tyrode solution at 37 degrees C. The Tyrode solution on the outer, mucosal side of intestinal segments contained 0.3 microM digoxin. Samples from the internal serosal side of the intestinal sacs were taken at 30, 60 and 120 min after the start of the experiments. The concentration of digoxin in the samples of fluid were determined using a radioimmunoassay method. The effect of nimodipine (0.1 and 0.2 mM) on digoxin absorption was also evaluated on the terminal segment of rat intestine. The interaction of nimodipine (0.5 mg/kg) and digoxin (0.2 mg/kg) was investigated in vivo when they were given perorally to rats. The duodenal absorption of digoxin was lower than in the small intestine. The highest absorption occurred in the terminal segment of the small intestine. Nimodipine increased the absorption of digoxin from the terminal segment of intestine in vitro, while it did not affect the serum digoxin concentration in vivo.
Topiramate, unlike gabapentin, lamotrigine and tiagabine, resembles phenytoin and carbamazepine since it had been used as an antinociceptive drug in empirical treatment of neuropathic pain in humans, before its systemic and planned research was conducted in animal models of pain. Chronic administration of topiramate, at the dose of 50 mg/kg/day, significantly diminished the mechanical sensitivity and shortened the period of allodynia in the Seltzer mononeuropathy model in rats.
We studied the effect of administering glycine, a non-essential amino acid, on liver collagen content and its characteristics in experimental hepatotoxic Wistar rats. All the rats were fed standard pellet diet. Hepatotoxicity was induced by orally administering ethanol (7.9 g kg(-1)) for 30 days. Control rats were given isocaloric glucose solution. Glycine was administered subsequently at a dose of 0.6 g kg(-1) po every day, along with alcohol for the next 30 days. Alcohol administration significantly elevated the levels of liver hydroxyproline and total collagen content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation, whereas it significantly decreased the solubility of liver collagen as compared with the control rats. Simultaneous glycine supplementation to alcohol-fed rats significantly reduced the levels of liver hydroxyproline and total collagen content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation and enhanced the solubility of liver collagen as compared with the unsupplemented alcohol-fed rats. In conclusion, administration of glycine had a positive influence both on the quantitative and qualitative properties of hepatic collagen in alcoholic liver injury.
