Effects of vasoactive intestinal peptide (VIP) on scopolamine-induced amnesia in the rat.

The effects of vasoactive intestinal peptide (VIP) on spatial cognitive deficits induced in the rat by injections of scopolamine were examined in a radial arm maze. A single intraperitoneal (i.p.), subcutaneous (s.c.) or intracerebroventricular (i.c.v.) injection of VIP inhibited the reduction in the number of initial correct responses in rats with scopolamine-induced amnesia. The inhibition was associated with a bell-shaped dose-response curve. Thus, VIP appears to have an ameliorating effect on spatial cognitive deficits induced by scopolamine in the rat.