Stimulus effects of delta(9)-THC and its interaction with naltrexone and catecholamine blockers in rats.

Rats trained in a T-shaped maze to discriminate the effects of i.p. injections of delta(9)-tetrahydrocannabinol (delta(9)-THC, 4 mg/kg) and the effects of the vehicle were tested for antagonism and generalization to the delta(9)-THC stimulus by naltrexone (4 mg/kg), haloperidol (0.32 mg/kg), propranolol (20 mg/kg), and phenoxybenzamine (10 mg/kg). None of these drugs blocked the delta(9)-THC stimulus, nor were they found to generalize to delta(9)-THC.