Selective antagonism of acute ethanol-induced motor disturbances by centrally administered Ro 15-4513 in mice.

Results of the present investigation demonstrated that Ro 15-4513 when given ICV selectively antagonized ethanol-induced motor disturbances at doses that did not produce motor incoordination and lacked proconvulsant activity. Ro 15-4513 in 10-, 15-, and 22-ng doses antagonized, roughly in a dose-dependent manner, ethanol-induced motor incoordination. The 10-ng dose produced an optimal effect with nearly complete antagonism within 30 min postethanol. The higher, 15 and 22 ng, doses of Ro 15-4513 antagonized, as well as probably reversed, ethanol-induced motor incoordination. The stimulation and inhibition of spontaneous motor activity by 1 and 2 g/kg IP ethanol, respectively, were also selectively antagonized by Ro 15-4513. Neither an alteration in the latency and/or duration of pentylenetetrazol-induced convulsions nor an antagonism to sodium pentobarbital-induced motor incoordination and inhibition of spontaneous motor activity by Ro 15-4513 at dose levels that showed antiethanol effects were observed. Only the 150-ng dose of Ro 15-4513, which exhibited intrinsic activity as proconvulsant, attenuated sodium pentobarbital-induced motor incoordination. When given alone at doses higher than those used in motor coordination experiments, Ro 15-4513 markedly increased spontaneous motor activity dose dependently.     

Age-dependent effects of stress on ethanol-induced motor activity in rats

Rationale

It is important to study age-related differences that may put adolescents at risk for alcohol-related problems. Adolescents seem less sensitive to the aversive effects of ethanol than adults. Less is known of appetitive effects of ethanol and stress modulation of these effects.

Objectives

This study aims to describe the effects of acute social or restraint stress on ethanol-precipitated locomotor activity (LMA), in adolescent and adult rats. Effects of activation of the kappa system on ethanol-induced LMA were also evaluated.

Methods

Adolescent or adult rats were restrained for 90 min, exposed to social deprivation stress for 90 or 180 min or administered with the kappa agonist U62,066E before being given ethanol, and assessed for LMA.

Results

Adolescents were significantly more sensitive to the stimulating, and less sensitive to the sedative, effects of ethanol than adults. Basal locomotion was significantly increased by social deprivation stress in adult, but not in adolescent, rats. U62,066E significantly reduced basal and ethanol-induced locomotion in the adolescents. Corticosterone and progesterone levels were significantly higher in adolescents than in adults.

Conclusions

Adolescents exhibit greater sensitivity to ethanol-induced LMA and reduced sensitivity to ethanol-induced motor sedation than adult rats. Ethanol’s effects on motor activity were not affected by acute stress. Unlike adults, adolescents were insensitive to acute restraint and social deprivation stress but exhibited motor depression after activation of the endogenous kappa opioid receptor system.     

Role of endothelial adenosine receptor-mediated vasorelaxation in ethanol-induced hypotension in hypertensive rats

Our previous findings showed that chronic ethanol feeding lowers blood pressure in spontaneously hypertensive rats. The present study investigated the role of the adenosine receptor-endothelial nitric oxide (NO) pathway in the hypotensive response to ethanol. Changes in blood pressure were evaluated in radiotelemetered pair-fed rats receiving liquid diet with or without ethanol (2.5% or 5%, w/v) for 12 weeks. The vasorelaxant activity of the adenosine analogue 5'-N-ethylcarboxamidoadenosine (NECA) in isolated aortic rings obtained from ethanol and control rats were evaluated. Ethanol (2.5% and 5%) lowered blood pressure in a dose-dependent manner. The hypotension started at week 1, reached its maximum at week 4 and remained so thereafter. In aortas with intact endothelium, NECA (10(-10) to 10(-4) M) produced a concentration-dependent relaxation of the phenylephrine-precontracted aortas. Compared with control rats, ethanol (2.5% and 5%) caused significant and concentration-related increases in NECA responses. This effect of ethanol was attenuated by the adenosine receptor antagonist 8-sulfophenyltheophylline and the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA). Further, endothelium denudation abolished the ethanol-evoked enhancement of NECA responses. The vasorelaxant responses to acetylcholine or sodium nitroprusside in aortic rings were not influenced by ethanol. In conclusion, the present findings suggest that chronic ethanol enhances the NO-dependent vasorelaxant responses to adenosine receptor activation and this may explain, at least partly, the mechanism of the hypotensive effect of ethanol in spontaneously hypertensive rats.     

Functional correlation between subclasses of brain adenosine receptor affinities and ethanol-induced motor incoordination in mice

To further investigate if the modulation of ethanol-induced motor incoordination is by brain adenosine A1 and/or A2 receptor, adenosine analogs with wide variability in their affinity for A1 and A2 subtypes were administered ICV and their effect on ethanol-induced (IP) motor incoordination was evaluated by rotorod. A dose-dependent marked accentuation of ethanol-induced motor incoordination by adenosine agonists (CHA, NECA, CPA, DCCA) tested, with nearly no effect on normal motor coordination in the absence of ethanol, was observed. There was a positive correlation between A2 affinity, A2/A1 affinity ratio but a negative correlation between A1 affinity and the potency (ED50) of adenosine agonists to accentuate ethanol-induced motor incoordination. However, with the high potency of CHA and NECA, both having significant affinity for A1 and A2 receptors, together with the well known membrane perturbation by ethanol, it seems difficult to rule out until more information becomes available the contribution of A1 receptor activation to adenosine modulation of ethanol-induced motor incoordination. The high density of high affinity A2 (A2a) in the striatum and of A1 in the cerebellum and several brain areas and the known importance of these two brain areas in the motor control, indirectly supports or at least provides a circumstantial evidence for a functional correlation between ethanol-induced motor incoordination and brain adenosine receptors.     

Methamphetamine facilitates ethanol-induced depressions in cerebellar purkinje neurons of prazocin- or DSP4-treated rats

Prepulse inhibition (PPI) is the normal reduction in startle reflex that occurs when a startling stimulus is preceded by a weak prepulse. PPI is reduced in patients with schizophrenia and in rats after central dopamine (DA) activation. The DA agonist-induced disruption of PPI in rats may thus model some features of impaired sensorimotor gating in schizophrenia. Ascending DAergic and descending glutamatergic fibers converge within the nucleus accumbens (NAC), and interactions at this DA-glutamate interface have been implicated in the pathophysiology of schizophrenia. In this study, we examined the role of NAC DA-glutamate interactions in the regulation of PPI in rats. Intra-NAC infusion of the non-NMDA antagonist, CNQX, attenuated the PPI-disruptive effects ofd-amphetamine (AMPH), but CNQX did not affect PPI when injected alone, nor did it reverse the PPI-disruptive effects of the direct D₂/D₃ agonist quinpirole. Intra-NAC infusion of the non-NMDA agonist AMPA significantly reduced PPI. The PPI-disruptive effects of AMPA were blocked by haloperidol and by 6-hydroxydopamine (6OHDA) lesions of the NAC. These data suggest that the PPI-disruptive effects of AMPH are dependent on tonic non-NMDA receptor activation in the NAC, and that non-NMDA receptor activation in the NAC results in a DA-dependent reduction in PPI. The parsimonious interpretation of these data is that non-NMDA glutamate receptors in the NAC facilitate presynaptic DA function, and that this DA-glutamate interaction is a critical regulatory substrate of sensorimotor gating.     

Ontogeny of ethanol-induced motor impairment following acute ethanol: Assessment via the negative geotaxis reflex in adolescent and adult rats

Adolescent rats have been observed to be less sensitive than adults to a number of ethanol effects that may serve as feedback cues to reduce further ethanol intake. Among these findings are a few reports of attenuated sensitivities of adolescents to ethanol-induced motor impairment. The purpose of the present study was to further explore potential age-related differences in ethanol-induced motor impairment in both male and female adolescent (postnatal day [P]28-32), and adult (P68-72) Sprague-Dawley rats using an inclined plane assessment of the negative geotaxis reflex. Adult males displayed significant motor impairment at 1.5 g/kg, whereas adolescent males required higher doses, showing significant motor impairment only at doses of 2.25 g/kg ethanol or greater. Intoxicated practice did not significantly influence level of motor impairment at either age. When female rats of both ages were separately analyzed in terms of their response to ethanol, a dose of 1.5 g/kg ethanol was found to significantly impair adults, whereas adolescent females showed significant motor impairment when challenged with 2.25 g/kg but not 1.5 g/kg ethanol. Yet when the 1.5 g/kg data of females at the two ages were directly compared, no significant age difference was seen at this dose. These data document an attenuated sensitivity of adolescent relative to adult rats to the motor impairing effects of ethanol using a stationary inclined plane test, an effect particularly robust in male animals, and demonstrates the utility of this test for assessment of motor coordination in adolescent and adult rats.     

Lack of tolerance to ethanol-induced motor impairment on accelerod performance in rats.

The effect of ethanol on rats was investigated at increasing rates of acceleration for bar rotation speed. Ethanol was given to rats by a liquid diet starting with 2.4% ethanol (v/v) for 3 days. Then the ethanol concentration was increased to 4.8% (v/v) for 3 days and finally to 7.2% (v/v) for 15 days. Accelerod performance was recorded before and throughout 20 days of ethanol intake. Mean blood ethanol levels were 266.34+/-13.11 and 285.20+/-9.77 mg/dl on the 7th and 15th days of ethanol (7.2% v/v) consumption, respectively, as measured in a parallel group of animals. Ethanol produced significant concentration-dependent impairments in the accelerod performance of rats. The motor impairment effect of ethanol was most prominent in the test using the greatest rate of acceleration (from 0 to 79 rpm within 2 min). The impairment effect of ethanol on accelerod performance occurred throughout the period of ethanol exposure. Our results indicate that motor impairment on the accelerod performance test produced by an ethanol liquid diet depends on the concentration of ethanol and the rate of acceleration. In addition, under free-access conditions accelerod performance may not be a suitable behavioral test for detecting tolerance development to ethanol in rats.     

Involvement of 5-hydroxytryptamine in the intestinal motor disturbances induced by mast cell degranulation in rats

Fasted rats with chronically implanted electrodes were used for investigation of the effects of mast cell degranulation induced by compound 48/80 and BrX-537A and their antagonism by previous administration of 5-hydroxytryptamine (5-HT) antagonists on duodenal and jejunal myoelectric activity. Administered i.p., both 48/80 (1 mg/kg i.p.) and BrX-537A (2 mg/kg i.p.) abolished the intestinal spiking activity of duodeno-jejunum with a progressive recovery, BrX-537A being less active. These effects were dose-related. Injected prior to 48/80, methysergide (1 mg/kg) reduced by about 80% both duodenal and jejunal inhibition of spiking activity with early recovery of a normal pattern. In contrast, ketanserin (1 mg/kg) had selective reducing effects on the duration of the spiking inhibition induced by 48/80 and BrX-537A on the duodenum only. Zacopride (1 mg/kg) and ICS 205-930 (50 micrograms/kg) shortened and suppressed, respectively, the inhibition of intestinal spiking activity with early restoration of intestinal motility in both duodenum and jejunum. We conclude that, in fasted rats (i) the degranulation of peritoneal mast cells induces alterations in intestinal myoelectric activity through the release of 5-HT (ii) these effects are mainly mediated through both 5-HT1 and 5-HT3 receptors.     

Protective effect of Matricaria chamomilla on ethanol-induced acute gastric mucosal injury in rats

The antiulcerogenic and antioxidant properties of Matricaria chamomilla L. (Compositae) hydroalcoholic extract (MCE) on ethanol-induced gastric mucosal injury were investigated in rats. After the induction of gastric mucosal injury, all groups were sacrificed; the gastric ulcer index was calculated, and malondialdehyde (MDA) and reduced glutathione (GSH) in whole blood and gastric tissue, and serum ascorbic acid, retinol, and β-carotene levels were measured in all groups. Pretreatment with MCE at some doses significantly reduced gastric lesions. Again, some doses of MCE significantly reduced the MDA, and significantly increased GSH levels in gastric tissue or whole blood. Serum β-carotene and retinol levels were significantly higher in the 200?mg/kg MCE-administered group with respect to control. As a result, MCE clearly has a protective effect against ethanol-induced gastric mucosal lesions, and this effect, at least in part, depends upon the reduction in lipid peroxidation and augmentation in antioxidant activity.     

Inhibition of ethanol-induced excitation in mice and rats by α-methyl-p-tyrosine

Small doses of ethanol (1 or 2 g/kg 20% w/v) caused increased motor activity in rats and mice as measured by an Animex activity meter. This effect was prevented by pretreatment with the tyrosine hydroxylase inhibitor -methyl-p-tyrosine methyl ester hydrochloride, in doses of 40 or 200 mg/kg which per se caused no significant depression of motor activity. The data implicate a role for newly synthesized catecholamines in ethanol-induced motor stimulation.     

Enhanced caspase activity during ethanol-induced apoptosis in rat cerebellar granule cells

The effects of ethanol on cerebellar granule cell death were examined in cultures maintained for either 5 days in vitro (immature) or 8 and 12 days in vitro (mature). Ethanol did not alter cell survival under the usual growth conditions (i.e., 10% serum and 25 mM KCl). However, in mature cultures ethanol enhanced apoptosis induced by either serum withdrawal or incubation in non-depolarizing media. In immature cultures, serum deprivation, but not non-depolarizing media, resulted in granule cell death that was enhanced by ethanol. Serum removal increased both cleavage of the caspase-specific substrate N-acetyl-Asp-Glu-Val-Asp-7 amino-4-methylcoumarin (Ac-DEVD-amc) and the amount of active caspase-3. Inclusion of ethanol during the serum deprivation augmented Ac-DEVD-amc cleavage without further increasing the amount of active caspase-3. This study demonstrates that when neurotrophic factors are limiting, ethanol is toxic to cerebellar granule cells regardless of maturation status. The ability of ethanol to promote apoptosis involves an increase in caspase activity, but this does not entail an increase in the proteolytic activation of caspase-3.     

Rebound hyperthermia follows ethanol-induced hypothermia in rats

We have recently described a telemetry/micro-computer system to monitor core temperatures in rats. We implant a miniature transmitter (Mini-mitter) into the peritoneal cavity of the rat, allowing us to obtain temperatures around the clock without handling the animals or disturbing the light-dark cycle. In the present study we describe the temperature effects of ethanol doses ranging from 2 to 6 g/kg. Baseline temperatures were collected for 2 days before drug was administered. Subsequent computer analysis then allowed us to compare experimental results in each animal with its own baseline temperature to allow for individual and circadian temperature differences. In preliminary studies we observed the well-known dose-dependent hypothermic effect of ethanol. However, by observing animals continually over 4 days we also observed a period of rebound hyperthermia beginning at about the time of complete ethanol elimination and persisting for several days. During this period daytime temperatures remained at the normally high night-time level. This may be evidence of a mild abstinence syndrome, or alternatively, may be due to a disruption of the normal circadian temperature rhythm.Preliminary work presented at the 33rd Fall Meeting of the American Society of Pharmacology and Experimental Therapeutics, Louisville, KY, August 1982, and at the 28th Annual Meeting of the Western Pharmacology Society, Jan. 20–25, 1985, Tahoe City, CA     

Verapamil worsens ethanol-induced gastric ulcers in rats

The effect of verapamil on ethanol-induced gastric ulceration was investigated in rats. Orally administered ethanol (0.5 ml), 10, 20 or 40% v/v, dose dependently produced glandular lesions, ranging from petechiae to haemorrhagic ulcers. These lesions were worsened by verapamil (2, 4 or 8 mg/kg given intraperitoneally (i.p.) 30 min beforehand) in the 30 min and 2 h ethanol-exposure experiments. However, ethanol ulceration or its aggravation by verapamil was antagonised by calcium gluconate (112 or 224 mg/kg given per os (p.o.) 30 min before ethanol administration) in a dose-related manner. These findings suggest that intracellular calcium depletion in the gastric glandular mucosa may account for ethanol ulceration and the ulcer-aggravating action of verapamil.     

Attenuation of paraquat-induced motor behavior and neurochemical disturbances by L-valine in vivo

Alterations of motor behavioral patterns and monoamine contents in the discrete rat brain areas after acute paraquat exposure (3, 5, 10, 20 mg/kg, s.c.) have been studied. The results showed that paraquat at the doses of 5, 10, and 20 mg/kg significantly reduced locomotive, stereotypic, and rotational behaviors. Significant decreases of norepinephrine (NE) contents in cortex and hypothalamus, as well as striatal contents of dopamine (DA) and its acidic metabolites, were detected. In addition, L-valine (200 mg/kg, i.p.) significantly attenuated paraquat-induced toxicity at moderate dose (5 mg/kg) but not at high dose (20 mg/kg). The results provide evidence that paraquat can enter the brain as illustrated by the alterations in the motor behavioral pattern and neurochemical contents. Furthermore, the attenuation effect of L-valine against systemic administration of paraquat-induced motor behaviors was detected, with a slightly protective effect on paraquat-induced neurochemical alterations.     

Enhancement by glutathione depletion of ethanol-induced acute hepatotoxicity in vitro and in vivo

Ethanol at initial concentrations between 0.75 and 6 g/l produced a dose-dependent release of the enzymes glutamic-pyruvic-transaminase and sorbitol dehydrogenase (GPT, SDH) from the isolated perfused rat liver. At the concentration of 6 g/l, it also decreased the oxygen consumption and elevated the calcium content of the isolated livers. These toxic effects of ethanol were significantly enhanced in livers, the glutathione content of which had been depleted by pretreatment with phorone. Ethanol-induced toxicity in glutathione-depleted isolated livers could be prevented both by inhibition of alcohol dehydrogenase with 4-methylpyrazole and of xanthine oxidase with allopurinol. In rats, in vivo, 1.6 g/kg ethanol injected intravenously produced a small increase in serum GPT and SDH concentrations 4 h after its administration. This increase in enzyme activities was several-fold higher and longer lasting in rats pretreated with phorone. Glutathione depletion per se did not induce hepatotoxicity in vitro or in vivo. Since glutathione is involved in several lines of defense against oxidative damage, our results of an enhanced susceptibility of glutathione-depleted livers to ethanol toxicity favour the hypothesis that ethanol exerts its hepatotoxic action via an activation of molecular oxygen.     

Learning factor in rapid tolerance to ethanol-induced motor impairment.

Exposure of male Wistar rats to a single moderate dose (1.7 g/kg, IP) of ethanol (EtOH), followed by intensive intoxicated practice on the moving belt apparatus (a total of 12 min during the first hour after EtOH injection), results in functional tolerance to the motor-impairing effects of a second dose given either 8 or 24 h later. In the absence of intoxicated practice, or after a considerably reduced opportunity for it (a total of 4 min during the first hour after EtOH injection), the same dose of EtOH fails to produce tolerance. Thus, not only the opportunity to practice, but also its extent and possibly its quality are important determinants in the rapid development of intersessional tolerance. In contrast to its rapidity of development, no significant loss of this tolerance is evident three weeks after the tolerance acquisition sessions.     

高效液相色谱法测定大鼠心肌中腺苷的含量

目的：建立高效液相色谱法测定大鼠心肌组织中腺苷的含量。方法 SD大鼠随机分为心肌缺血再灌注组（ IRI）、106 Treg细胞转输＋IRI组、107Treg细胞转输＋IRI 组和假手术对照组。色谱柱为 VP-ODS C18柱（250mm ×4.6mm,5μm）;流动相为甲醇：10mmol· L-1乙酸铵（10∶90）;流速为1.0mL· min -1;柱温25℃;检测波长260nm;进样量20μL。结果腺苷的标准液与峰面积均呈良好的线性关系（r＝1.000）,平均回收率分别为100.1％。日内和日间精密度分别在4.56％和4.84％以下。结论本法操作简便、准确、快速,可以用于测定大鼠心肌组织中腺苷的含量。     

Calcium and ethanol-induced gastric mucosal damage in rats

The effects of graded doses of ethanol on stomach mucosal damage and calcium levels were studied in rats. The influence of verapamil and/or calcium chloride on these changes was also investigated. Orally administered ethanol (20, 50 or 80% v/v) markedly decreased gastric glandular tissue calcium and it concentration dependently produced mucosal lesions. Pretreatment with verapamil (2.5 or 5 mg/kg, i.p.) dose dependently lessened glandular wall calcium levels and worsened ethanol-induced mucosal damage. Calcium chloride (50 mg/kg, i.p.) significantly prevented ethanol-induced gastric calcium depletion; it also dose dependently antagonized the damaging effect of ethanol as well as the lesion-intensifying action of verapamil. The findings that verapamil potentiated, whereas calcium chloride prevented, ethanol-induced glandular mucosal damage and tissue calcium changes indeed suggest that altered gastric cell calcium levels could be closely related to the mucosal lesions produced by ethanol in rats.     

L-carnitine inhibits ethanol-induced gastric mucosal injury in rats

L-carnitine is a quaternary amine that is essential for the normal oxidation of long-chain fatty acids by mitochondria. It is known that L-carnitine and its derivatives prevent the formation of reactive oxygen species, scavenge free radicals and protect cells from peroxidative stress. Oxygen-derived free radicals and lipid peroxidation products play a critical role in the pathogenesis of ethanol-induced gastric mucosal injury. The aim of the present study was to determine the effect of L-carnitine on lipid peroxidation induced by ethanol in the rat stomach. In our study, gastric mucosal injury was induced by the intragastric administration of 1 ml of absolute ethanol. Test compounds were given to rats by gavage 30 min before the ethanol administration. The animals were killed 60 min after the administration of ethanol. The stomach of each animal was removed. Mucosal damage was evaluated by macroscopic examination, histological analysis and by measurement of lipid peroxidation and glutathione activity. The intragastric administration of ethanol induced hyperemia and hemorrhagic erosions in the rat stomachs. L-carnitine significantly prevented gastric ulcerogenesis induced by ethanol and decreased the ulcer index. Plasma and gastric lipid peroxidation that was increased significantly by ethanol was decreased after treatment with L-carnitine. Ethanol treatment decreased significantly the gastric glutathione levels, and pretreatment with L-carnitine increased them significantly. Based on these data, the beneficial effects of L-carnitine on ethanol-induced gastric mucosal injury may be attributed to its antiperoxidative effects.