Role of vasopressin V1a receptor in ∆
Cannabis is a widely used illicit substance. ∆ The present study was designed to examine the possible involvement of V1a and V1b receptors in THC-induced catalepsy-like immobilization. The induction of catalepsy following treatment with THC (10 mgkg, i.p.) or haloperidol (1 mgkg, i.p.) was evaluated in wild-type (WT), V1a receptor knockout (V1aRKO), and V1b receptor knockout (V1bRKO) mice. The effect of treatment with the selective 5-hydroxytryptamine THC and haloperidol markedly caused catalepsy in V1bRKO mice as well as in WT mice. However, V1aRKO mice exhibited a reduction in catalepsy induced by THC but not by haloperidol. WAY100635 dramatically enhanced THC-induced catalepsy in V1aRKO mice. Although VMAX-357 (10 mgkg, p.o.) but not ORG-52186 significantly attenuated THC-induced catalepsy, it had no significant effect on the enhancement of THC-induced catalepsy by WAY100635 in ddY mice. These findings suggest that V1a receptor regulates THC-induced catalepsy-like immobilization.