Psychopharmacology
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Gamma (gamma) is a recently proposed statistic that quantifies and describes the repetitive patterns of locomotion (locomotor stereotypy) exhibited by amphetamine-treated rats in an open field. The time-course of locomotor stereotypy after 1, 2, 3, and 4 mg/kg amphetamine was investigated in this research. Locomotor stereotypy was often evident during the first observation period after amphetamine. ⋯ Contrary to expectations, rats injected with 2 mg/kg amphetamine exhibited the highest and most sustained increase in gamma. We conclude that locomotor stereotypy is an important component of the behavioral effects of amphetamine in rats. Whether locomotor stereotypy and focused stereotypy are similar phenomena is still unclear.
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Two experiments were run in which rats were rewarded with food for running in a straight alley at one trial a day, followed by extinction of the running response. During acquisition of the response, reward was delivered either on a continuous reinforcement (CRF) or on a quasirandom 50% partial reinforcement (PRF) schedule. The groups given PRF were more resistant to extinction than those given CRF, the well-known partial reinforcement extinction effect. ⋯ At the end of Experiment 2 only [3H]-flunitrazepam binding was measured in either the presence or absence of added gamma-aminobutyrate (GABA) in homogenates of hippocampi dissected from the animals that had received behavioural training. The drug affected running speeds during both acquisition and extinction in different ways depending upon the schedule of reinforcement (CRF or PRF) and also gave rise to enhanced GABA stimulation of [3H]-flunitrazepam binding. The results are discussed in relation to the hypothesis that the neurochemical pathways by which reinforcement schedules modify behaviour include a step influenced by benzodiazepine receptors.
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Clinical Trial Controlled Clinical Trial
Acute marijuana effects on social conversation.
The present study assessed the acute effects of smoked marijuana on social conversation. Speech quantity was recorded continuously in seven moderate marijuana users during separate 1 h experimental sessions following the paced smoking of 0, 1.01, 1.84, and 2.84% THC marijuana cigarettes. Subjects engaged in conversation with undrugged partners who smoked placebo marijuana cigarettes. ⋯ Partners showed no effects in speech quantity or self-reports of drug effects that were systematically related to the doses administered to the subject pair members. The effects on speech quantity observed in the present study after acute dosing are similar to the effects on social conversation reported previously during chronic marijuana dosing. Marijuana appears to be an exception to the general rule that drugs of abuse increase verbal interaction.
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Randomized Controlled Trial Comparative Study Clinical Trial
A double blind comparison of alprazolam, diazepam and placebo in the treatment of anxious out-patients.
The anxiolytic effects of alprazolam, a triazolobenzodiazepine, were evaluated in a double-blind 28-day comparison with diazepam and placebo in 46 out-patients suffering from anxiety states of moderate to severe intensity. Alprazolam 1.5-3 mg per day was found to be of at least equivalent anxiolytic effect to 15-30 mg diazepam per day, and there was evidence of antidepressant activity by alprazolam, but not diazepam, in neurotic depression. ⋯ Laboratory data showed no changes attributable to alprazolam even in a patient who swallowed 15 capsules (7.5 mg). It was concluded that alprazolam is a safe and effective anxiolytic which is well-tolerated and also shows some antidepressant activity.
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Clinical Trial Controlled Clinical Trial
Action of cannabidiol on the anxiety and other effects produced by delta 9-THC in normal subjects.
The object of the experiment was to verify whether cannabidiol (CBD) reduces the anxiety provoked by delta 9-THC in normal volunteers, and whether this effect occurs by a general block of the action of delta 9-THC or by a specific anxiolytic effect. Appropriate measurements and scales were utilized and the eight volunteers received, the following treatments in a double-blind procedure: 0.5 mg/kg delta 9-THC, 1 mg/kg CBD, a mixture containing 0.5 mg/kg delta 9-THC and 1 mg/kg CBD and placebo and diazepam (10 mg) as controls. Each volunteer received the treatments in a different sequence. ⋯ This antagonism does not appear to be caused by a general block of delta 9-THC effects, since no change was detected in the pulse-rate measurements. Several further effects were observed typical of CBD and of an opposite nature to those of delta 9-THC. These results suggest that the effects of CBD, as opposed to those of delta 9-THC, might be involved in the antagonism of effects between the two cannabinoids.