No abstract

The marijuana-induced acute memory impairment was assessed in a double-blind, crossover experiment. Twelve males smoked NIDA-supplied cigarettes containing 1.2% delta-9-tetrahydrocannabinol (THC) or cannabinoid-exhausted marijuana (placebo) in counterbalanced order on 2 days 1-3 weeks apart. Practice, pre- and postsmoking test sessions were conducted with the Paced Auditory Serial Addition Test, Stroop Color and Word Test, and alternate forms of the Randt Memory Battery and the Controlled Oral Word Association Test. A significantly greater number of short story omissions and intrusions occurred in delayed free recall after marijuana. Immediate and sustained attention, controlled retrieval from semantic memory, and speed of reading and naming colors were not affected. The Stroop interference effect was significantly greater following marijuana. Subjects appeared to experience parallel difficulties in inhibiting associations to the new material and inhibiting the overlearned response of reading in a new learning task. Marijuana may compromise associative control, presumably a cognitive process inherent in memory function.

No abstract

Diltiazem, a benzothiazepine calcium channel antagonist, was given to six healthy men as a single 60 mg oral dose 120 min before IV injection of cocaine (0.2 mg/kg) in a double-blind, placebo-controlled, two-session study. Diltiazem alone produced no significant effects. Cocaine increased blood pressure, heart rate, pupil size and subjective "high" ratings, and decreased skin temperature. Diltiazem pretreatment diminished the cocaine effect on skin temperature, but did not otherwise alter the response to cocaine. Calcium channel antagonists diminish the effects of cocaine in vitro and in animals. Dosage considerations may be critical because of the differential sensitivity of various tissues to calcium channel antagonists.