Psychopharmacology
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Comparative Study Clinical Trial
Comparison of smoked marijuana and oral Delta(9)-tetrahydrocannabinol in humans.
Although smoked marijuana contains at least 60 cannabinoids, delta(9)-tetrahydrocannabinol (delta(9)-THC) is presumed to be the cannabinoid primarily responsible for many marijuana-related effects, including increased food intake and subjective effects. Yet, there has been no systematic comparison of repeated doses of oral delta(9)-THC with repeated doses of smoked marijuana in the same individuals. ⋯ These results indicate that the behavioral profile of effects of smoked marijuana (3.1% delta(9)-THC) is similar to the effects of oral delta(9)-THC (20 mg), with some subtle differences.
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Clinical Trial
The moderating effect of anxiety sensitivity on caffeine-induced hypoalgesia in healthy women.
Caffeine is an analgesic adjuvant, but also has panicogenic properties. Anxiety sensitivity is a trait vulnerability factor related to negative responses to pain, and is known to moderate negative psychological responses to caffeine. ⋯ These results suggest that the analgesic effects of caffeine may depend on anxiety sensitivity status, and that the fear of bodily sensations should be considered in pain management programmes.
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The dorsal periaqueductal gray matter (dPAG) has been implicated in the modulation of defensive behavior. Electrical stimulation of this structure can be used as an unconditioned stimulus to produce a conditioned fear reaction expressed by freezing, antinociception, and autonomic responses. ⋯ (1) Conditioned freezing and antinociception are modulated by benzodiazepine mechanisms into dPAG. (2) 5-HT(2) receptors seem to regulate conditioned freezing behavior. However, conditioned antinociception was not affected by 13 nmol naltrexone. (3) Opioid mechanisms do not seem to be involved in the conditioned responses using electrical stimulation of the dPAG as unconditioned stimulus. Further studies with other opioid and 5-HT(2) receptor antagonists are still needed to confirm the conclusions drawn from the present work.