Comparison of voluntary ethanol intake by two pairs of rat lines used as genetic models of anxiety

The relationship between anxiety-related behaviors and voluntary ethanol intake was examined in two pairs of rat lines by the oral ethanol self-administration procedure. Floripa high (H) and low (L) rats selectively bred for contrasting anxiety responses in the open-field test, and two inbred strains, spontaneously hypertensive rats (SHR) and Lewis rats which are known to differ significantly when submitted to several behavioral tests of anxiety/emotionality, were used (9-10 animals/line/sex). No differences in the choice of ethanol solutions (2 percent, days 1-4, and 4 percent, days 5-8, respectively) in a 2-bottle paradigm were detected between Floripa H and L rats (1.94 ± 0.37 vs 1.61 ± 0.37 g/kg for ethanol intake on day 8 by the Floripa H and L rat lines, respectively). Contrary to expectations, the less anxious SHR rats consumed significantly more ethanol than Lewis rats (respective intake of 2.30 ± 0.45 and 0.72 ± 0.33 g/kg on day 8) which are known to be both addiction-prone and highly anxious. Regardless of strain, female rats consumed more ethanol than males (approximately 46 percent). The results showed no relationship between high anxiety and voluntary intake of ethanol for Floripa H and L rats. A negative association between these two variables, however, was found for SHR and Lewis rat strains. Data from the literature regarding the association between anxiety and alcohol intake in animal models are not conclusive, but the present results indicate that factors other than increased inborn anxiety probably lead to the individual differences in ethanol drinking behavior.

Strain-dependent effects of diazepam and the 5-HT2B/2C receptor antagonist SB 206553 in spontaneously hypertensive and Lewis rats tested in the elevated plus-maze

The 5-HT2B/2C receptor antagonist SB 206553 exerts anxiolytic effects in rat models of anxiety. However, these effects have been reported for standard rat strains, thus raising the issue of SB 206553 effects in rat strains displaying different levels of anxiety. Herein, the effects of SB 206553 in a 5-min elevated plus-maze test of anxiety were compared to those of the reference anxiolytic, diazepam, in two rat strains respectively displaying high (Lewis rats) and low (spontaneously hypertensive rats, SHR) anxiety. Diazepam (0.37, 0.75, or 1.5 mg/kg; 30 min before testing) increased in a dose-dependent manner the behavioral measures in SHR, but not in Lewis rats. On the other hand, SB 206553 (1.25, 2.5, or 5 mg/kg; 30 min before testing) failed to alter the anxiety parameters in both strains, whereas it increased closed arm entries in Lewis rats, suggesting that it elicited hyperactivity in the latter strain. Accordingly, the hypolocomotor effect of the nonselective 5-HT2B/2C receptor agonist m-chlorophenylpiperazine (1.5 mg/kg ip 20 min before a 15-min exposure to an activity cage) was prevented by the 1.25 and 2.5 mg/kg doses of SB 206553 in Lewis rats and SHR, respectively. Compared with SHR, Lewis rats may display a lower response to benzodiazepine-mediated effects and a more efficient control of locomotor activity by 5-HT2B/2C receptors

Combined effects of diethylpropion and alcohol on locomotor activity of mice: participation of the dopaminergic and opioid systems

The widespread consumption of anorectics and combined anorectic + alcohol misuse are problems in Brazil. In order to better understand the interactive effects of ethanol (EtOH) and diethylpropion (DEP) we examined the locomotion-activating effects of these drugs given alone or in combination in mice. We also determined whether this response was affected by dopamine (DA) or opioid receptor antagonists. A total of 160 male Swiss mice weighing approximately 30 g were divided into groups of 8 animals per group. The animals were treated daily for 7 consecutive days with combined EtOH + DEP (1.2 g/kg and 5.0 mg/kg, ip), EtOH (1.2 g/kg, ip), DEP (5.0 mg/kg, ip) or the control solution coadministered with the DA antagonist haloperidol (HAL, 0.075 mg/kg, ip), the opioid antagonist naloxone (NAL, 1.0 mg/kg, ip), or vehicle. On days 1, 7 and 10 after the injections, mice were assessed in activity cages at different times (15, 30, 45 and 60 min) for 5 min. The acute combination of EtOH plus DEP induced a significantly higher increase in locomotor activity (day 1: 369.5 + or - 34.41) when compared to either drug alone (day 1: EtOH = 232.5 + or - 23.79 and DEP = 276.0 + or - 12.85) and to control solution (day 1: 153.12 + or - 7.64). However, the repeated administration of EtOH (day 7: 314.63 + or - 26.79 and day 10: 257.62 + or - 29.91) or DEP (day 7: 309.5 + or - 31.65 and day 10: 321.12 + or - 39.24) alone or in combination (day 7: 459.75 + or - 41.28 and day 10: 427.87 + or - 33.0) failed to induce a progressive increase in the locomotor response. These data demonstrate greater locomotion-activating effects of the EtOH + DEP combination, probably involving DA and/or opioid receptor stimulation, since the daily pretreatment with HAL (day 1: EtOH + DEP = 395.62 + or - 11.92 and EtOH + DEP + HAL = 371.5 + or - 6.76; day 7: EtOH + DEP = 502.5 + or - 42.27 and EtOH + DEP + HAL = 281.12 + or - 16.08; day 10: EtOH + DEP = 445.75 + or - 16.64 and EtOH + DEP + HAL = 376.75 + or - 16.4) and NAL (day 1: EtOH + DEP = 553.62 + or - 38.15 and EtOH + DEP + NAL = 445.12 + or - 55.67; day 7: EtOH + DEP = 617.5 + or - 38.89 and EtOH + DEP + NAL = 418.25 + or - 61.18; day 10: EtOH + DEP = 541.37 + or - 32.86 and EtOH + DEP + NAL = 427.12 + or - 51.6) reduced the locomotor response induced by combined administration of EtOH + DEP. These findings also suggest that a major determinant of combined anorectic-alcohol misuse may be the increased stimulating effects produced...

Experimental anxiety and the reinforcing effects of ethanol in rats

In order to examine the relationship between anxiety and reinforcing effects of alcohol, drug-naive male Wistar rats weighing 250-300 g were classified as "anxious" and "non-anxious" in the elevated plus-maze test. A conditioned place preference test was then used to investigate the reinforcing effects of ethanol (EtOH) on these animals. On 2 alternate days, groups of "anxious", "non-anxious" and "normal" rats received intraperitoneal (ip) injections of EtOH (0.5, 1.0 or 1.5 g/kg) immediately before a 15-min confinement to the white compartment. On the 2 intervening days the same rats received ip injections of saline before confinement to the opposite compartment. On day 5, a 15-min free-choice test was carried out with no injections. Rats classified as "anxious" showed a significant, though not dose-dependent preference for all doses of ethanol compared to saline-treated animals. These data demonstrate that rats regarded as "anxious" are more sensitive to the reinforcing effects of EtOH than "non-anxious" and "normal" Wistar rats and emphasize the relevance of the basal levels of anxiety of rats when trying to detect the reinforcing effects of EtOH.

Memory-impairing effects of local anesthetics in an elevated plus-maze test in mice

Post-training intracerebroventricular administration of procaine (20 mug/mul) and dimethocaine (10 or 20 mug/mul), local anesthetics of the ester class, prolonged the latency(s) in the retention test of male and female 3-month-old Swiss albino mice (25-35 g body weight; N=140) in the elevated plus-maze (mean + SEM for 10 male mice: control= 41.2 + 8.1; procaine = 78.5 + 10.3; 10 mug/mul dimethocaine = 58.7 + 12.3; 20 mug/mul dimethocaine = 109.6 + 5.73; for 10 female mice: control = 34.8 + 5.8; procaine = 55.3 + 13.4; 10 mug/mul dimethocaine = 59.9 + 12.3 and 20 mug/mul dimethocaine = 61.3 + 11.1). However, lidocaine (10 or 20 mug/mul), an amide class type of local anesthetic, failed to influence this parameter. Local anesthetics at the dose range used did not affect the motor coordination of mice exposed to the rota-rod test. These results suggest that procaine and dimethocaine impair some memory process(es) in the plus-maze test. These findings are interpreted in terms of non-anesthetic mechanisms of action of these drugs on memory impairment and also confirm the validity of the elevated plusmaze for the evaluation of drugs effecting learning and memory in mice.

Anxiogenic action of acute but not repeated cocaine administration handling-habituate3d mice in the plus-maze test

The present study was designed to determine the putative anxiogenic effects of cocaine on the performance of mice in the elevated plus-maze test of anxiety. Male Swiss mice, weighing abouth 30 g, treated repeatedly with saline for 8 days and challenged with a single injection of cocaine 10 mg/kg, ip, 1 ml/100 g, on day 10, showed a clear reduction in the relative number (%) of entries and time spent on the open arms of the maze (30.5) ñ 4.5 and 29.4 ñ 5.0 vs 47.1 ñ 6.2 and 46.7 ñ 9.4, for the controls, respectively, N=7-8 animals). These data suggest an anxiogenic action of cocaine (10 mg/kg) for 8 days failed to alter the indices of anxiety in the test. These findings suggest that the emotional changes induced by the handling procedures for 8 days may be related to the occurrence of anxiogenic responses to cocaine by mice

Some clacium channel antagonists have no effect on the open-fied behavior of rats nor do they interact with cocaine

The behavioral effects of the calcium channel antagonists nifedipine (10 mg/Kg), diltiazem (10mg/Kg) and verapamil (10mg/Kg) administered intraperitoneally alone or in combination with the CNS stimulant cocaine (20mg/Kg) were investigated in rats using the open-field test. Calcium channel antagonists alone or combined with cocaine produced no significant effects on the number of rearing or number of ambulations. Cocaine inected alone significantly increased the frequency of ambulation. These data indicate that some calciun channel antagonists were not able to alter the behavioral effects induced by cocaine in rats in the open-field and thus do not support the view that calcium antagonists can reverse the effects of psychostimulant drugs

Behavioral and biochemical changes following reapeted administration of carbaryl to aging rats

Motor, sensory and thermoregulatoty function were examined in aging rats (12 months) following two schedules of repated po adminstration of the carbamate insecticide carbaryl and these effects were assessed in terms of blood cholinesterase activity. Administration of carbaryl (50 mg/Kg) by gavage daily for 30 days resulted in a resultad in a reduction of locomotor activity in thre open-field and an inhibition of cholinesterase activity within 30 min after the last treatment. Twenty-for h later, only the locomotor effect was evident. After 90 days of exposure to carbaryl in drinking water, no significant effects were observed. These findings suggest that repeated administration of carbaril to aging rats can induce an impairment of motor function and a reduction of cholinesterase activity, while tolerance develops in some other parameters

Cross self-administration of delta 9 tetrahydrocannabinol and D-amphetamine in rats

1. Schedule-induced intravenous self-injection of delta9 - tetrahydrocannabinol (delta9 -THC) and d-amphetamine was investigated in the same animals. 2. /rats self-injected significantly more amphetamine than delta9 -THC. However, the results suggested that delta9 -THC did not play a predisposing role to the increased amphetamine intake. When delta 9 -THC was reinstated after amphetamine response rates were drastically reduced. 3. It is conclued that the reinforcing effects of delta- -THC may be unrelated to its stimulant effects. The small number of responses for delta9 -THC is in agreement with reports of the poor reinforcing capability of cannabis compounds in rats

Progeria: estudo biopsicossocial de um caso. / Progeria: biopsychosocial study of a case

Os autores apresentam o estudo biopsicossocial de um caso de Progeria em adolescente de 17 anos de idade, de sexo feminino. O estudo e o resultado do seguimento multiprofissional adotado no Instituto da Crianca. Sao apresentados os aspectos socio-economicos e culturais, os relativos ao ambiente fisico e a alimentacao e o estudo psicologico (testes de nivel mental e de personalidade). Enfatiza-se o valor do tipo de seguimento adotado