Effects of chronic ingestion and withdrawal of sodium barbitone on learning in rats

Effect of Evolvulus alsinoides Linn. on learning behavior and memory enhancement activity in rodents

In the Ayurvedic system of medicine, the whole herb of 'Shankhpushpi' has been employed clinically for centuries for its memory potentiating, anxiolytic and tranquilizing properties. The present study was undertaken to investigate the effects of Evolvulus alsinoides (EA), considered as Shankhpushpi on learning and memory in rodents. Nootropic activity using Cook and Weidley's pole climbing apparatus, passive avoidance paradigms and active avoidance tests were used to test learning and memory. The ethanol extract of EA and its ethyl acetate and aqueous fractions were evaluated for their memory enhancing properties. Two doses (100 and 200 mg/kg p.o.) of the ethanol extract and ethyl acetate and aqueous fractions were administered in separate groups of animals. Both doses of all the extracts of EA significantly improved learning and memory in rats. Furthermore, these doses significantly reversed the amnesia induced by scopolamine (0.3 mg/kg i.p.). Nootropic activity was compared using piracetam as the standard. EA also exhibited potent memory enhancing effects in the step-down and shuttle-box avoidance paradigms.

Effect of Convulvulus pluricaulis Choisy. on learning behaviour and memory enhancement activity in rodents

The present study was undertaken to investigate the effects of Convulvulus pluricaulis (CP), considered as Shankhpushpi on learning and memory in rodents. Nootropic activity using Cook and Weidley's Pole Climbing Apparatus, passive avoidance paradigms and active avoidance tests were used to test learning and memory. The ethanolic extract of CP and its ethyl acetate and aqueous fractions were evaluated for their memory enhancing properties. Two doses (100 and 200 mg kg(-1) p.o.) of the ethanolic extract and ethyl acetate and aqueous fractions were administered in separate groups of animals. Both the doses of all the extracts of CP significantly improved learning and memory in rats. Furthermore, these doses significantly reversed the amnesia induced by scopolamine (0.3 mg kg(-1) i.p.). Nootropic activity was compared using piracetam as the standard. Moreover, CP has exhibited potent memory-enhancing effects in the step-down and shuttle-box avoidance paradigms. Further studies are necessitated to identify the exact mechanism of action.

Central nervous system activity of the methanol extract of Ficus platyphylla stem bark

The central nervous system (CNS) activity of the methanolic extract of Ficus platyphylla stem bark was studied on locomotor activity, pentobarbital sleeping time, exploratory behaviour, amphetamine-induced hyperactivity, apomorphine-induced stereotypy, active-avoidance and performance on tread mills (rota-rod), using mice and rats. The results revealed that the extract significantly reduced the locomotor and exploratory activities in mice, prolonged pentobarbital sleeping time in rats, attenuated amphetamine-induced hyperactivity and apomorphine-induced stereotypy in mice, dose-dependently. The extract significantly suppressed the active-avoidance response in rats, with no significant effect on motor co-ordination as determined by the performance on rota-rod. The results suggest that the extract may possess sedative principles with potential neuroleptic properties.

CNS pharmacological effects of the total alkaloidal fraction from Albizia inopinata leaves

The total alkaloidal fraction of Albizia inopinata leaves (FLA) was investigated for its central nervous system (CNS) effects. FLA (10 mg/kg, i.p.) significantly reduced (45%) the locomotor activity in mice. In addition, it inhibited the conditioned avoidance response behavior and induced ptosis in rats. On the other hand, FLA did not exert significant effect on catalepsy, but potentiated the haloperidol-induced catalepsy. No effect was observed on sleep induced by sodium pentobarbital or apomorphine-induced stereotypes.

Central depressant effects of reticuline extracted from Ocotea duckei in rats and mice

Neuropharmacological studies were carried out with reticuline, a benzylisoquinoline alkaloid, isolated from Ocotea duckei Vattimo. It was found that reticuline (50-100 mg/kg i.p.) produced alteration of behaviour pattern, prolongation of pentobarbital-induced sleep, reduction in motor coordination and D-amphetamine-induced hypermotility and suppression of the conditioned avoidance response. These observations suggest that reticuline possesses potent central nervous system depressant action.

Similar development of tolerance to barbital-induced inhibition of avoidance behavior and loss of righting reflex in rats

In order to determine if tolerance develops to the inhibition of avoidance behavior by the barbiturates, the effects of barbital on avoidance were determined in rats given barbital in their sole source of drinking water for 7 or 33 days. For comparison tolerance to the loss of righting reflex was also determined in other rats at the same time. All rats were trained by one 60-min session in a one-way active avoidance task; they were then put on the chronic drug administration schedule and then tested on the appropriate day after a single IP injection of 250 mg/kg sodium barbital. To assess the degree of tolerance, the brain level of barbital found at the biological endpoint--the loss of avoidance or loss of righting reflex--was compared in the chronic barbital treated rats and controls. A similar degree of tolerance developed to both effects of the drug and it appeared to be as great after 7 as after 33 days of chronic barbital treatment.