Effects of scopolamine on activity and passive avoidance learning in rats of different ages.

Abstract

A total of 320 albino CFE Sprague-Dawley rats aged 16-17, 20-21, 24-25, 28-29, and 70-85 days old were injected intraperitoneally with either scopolamine hydrobromide (SCOP-HBr) or scopolamine methylnitrate (SCOP-Me-NO-3) at 4 levels (0, .5, 1.9, or 2.0 mg/kg. The SCOP-HBr but not he SCOP-Me-NO-3 disrupted passive avoidance in Ss aged 20-28 days. A subsequent replication at higher doses (4.0, 8.0, and 16.0 mg/kg) with 56 70-84 day old adults and 64 16-day-old pups indicated that SCOP-HBr could disrupt passive avoidance in the adults but not in the pups. Results are consistent with the hypothesis that a cholinergic inhibitory system which mediates passive avoidance develops in the rat 16-20 days postnatally. (29 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)