Lack of tolerance to the anxiolytic effect of diazepam and pentobarbital following chronic administration in perinatally undernourished rats.

BORGHESE, C.; LAINO, C.H; CORDOBA, N.E; RUBIO, M.C.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 1998 vol. 46 p. 237 - 237

dult female rats, undernourished at perinatal age, were evaluated for anxiolytic action in the plus-maze test after acute and chronic administration of diazepam (DZP) and pentobarbital (PTB). Deprived (D) rats chronically treated with vehicle showed an increased anxiety as compared with control (C) animals. A single intraperitoneal (i.p.) administration of DZP (1 mg/kg) or PTB (7.5 mg/kg) produced similar anticonflict effect in both C and D rats. Tolerance to the anxiolytic effect of DZP and PBT developed in C rats after a 15-day administration schedule, whereas no tolerance was observed in D animals. Drug disposition was not altered after chronic treatment either in C or in D rats. g-aminobutyric acid (GABA)-mediated chloride uptake in microsacs of cerebral cortex of naive D rats was decreased as compared with naive C rats. After chronic DZP administration (1 mg/kg/day i.p. for 15 days), GABA-mediated 36Cl influx in brain cortex microsacs of C rats did not change; however, GABA effi