...this statement.

Quote Originally Posted by Pharmacol Biochem Behav. 2006 Jul 1; (Epub ahead of print)
Recently, cannabinoid receptor agonists have been reported to impair prepulse inhibition (PPI) of the startle reflex. In the current study, we examined the effect of Delta(9)-tetrahydrocannabinol (THC), the principal psychoactive component of cannabis, on the PPI, and found that THC (10 mg/kg, i.p.) impaired the PPI concomitant with a decrease in the startle response. Antipsychotics such as haloperidol (0.3 mg/kg, i.p.) and risperidone (0.1 mg/kg, i.p.), which are potent dopamine D(2) receptor antagonists, and SR141716 (10 mg/kg, i.p.), a CB(1) cannabinoid receptor antagonist, reversed these THC-induced PPI deficits. Moreover, THC (10 mg/kg) increased dopamine (DA) release in the nucleus accumbens but not medial prefrontal cortex over a 50-100-min period (time of PPI test) after treatment, and SR141716 (10 mg/kg) reversed this increase in DA release induced by THC. These results suggest that dopaminergic hyperfunction in the nucleus accumbens may be involved in THC-induced PPI deficits.