Effects of concurrent nicotinic antagonist and PCPA treatments on spatial and passive avoidance learning.

The present study investigates the effects of concurrent manipulations of nicotinic cholinergic receptors (mecamylamine 10 mg/kg, i.p.) and serotonin neurons (PCPA, 400 mg on each of 4 days) on spatial navigation (water maze, WM) and passive avoidance (PA) performance. PCPA treatment had no effect on WM navigation or PA performance of intact rats, but greatly aggravated mecamylamine induced performance deficit. Either single or combined treatments with hexamethonium (5.0 mg/kg, s.c.) and PCPA had no effect on WM or PA performance. These findings may suggest that nicotinic cholinergic receptors are also importantly involved in the cholinergic-serotonergic regulation of cognitive functioning.