Differential effect of vasopressin on open-field activity and passive avoidance behaviour following intracerebroventricular versus intracisternal administration in rats.

The effects of lysine8-vasopressin (LVP) on the open-field activity and passive avoidance behaviour in rats were studied following intracerebroventricular (i.c.v.) and intracisternal (c.m.) administration. Following i.c.v. administration, LVP caused a long-lasting facilitation of the passive avoidance behaviour and did not influence open-field activity. When injected into the cisterna magna, on the other hand, the same amount of LVP was without effect on the passive avoidance behaviour, while decreasing open-field activity. It is concluded that the site of injection in the cerebrospinal space might be of importance in determining the behavioural effects of neuropeptides.