| Popis: |
Publisher Summary This chapter presents recent developments in the pharmacology of the benzodiazepines. The benzodiazepines are a class of compounds that have been found to show marked antianxiety effects in human subjects. Clinical studies indicate that various members of this series also have anticonvulsant, muscle relaxant, and hypnotic properties. In addition, there are reports of psychostimulant activity. New insights into the mechanism of action of the benzodiazepines have been provided by research published during the period 1967–1971:(1) The major muscle relaxant actions occur in the central nervous system. The primary effect seems to be a reduction in the facilitatory influence of the reticular formation on spinal reflexes. A direct action on the spinal cord may also occur. (2) Central modulation of autonomic responses may involve a discrete depressant effect on sympathetic vasoconstrictor activity. (3) A behavioral characteristic of benzodiazepines is the release of previously suppressed responses. Thus, before drug treatment rats learn to press a lever that produces a food reward, while ignoring a lever that produces no reward. During the action of chlordiazepoxide hydrochloride, the number of unrewarded responses is increased. This action is attributed to a breakdown of inhibition. (4) Electrophysiological studies in rats and cats indicate that a major action of benzodiazepines is on the hippocampus. This finding is in contrast to the action of barbiturates, which seem to act primarily on the brainstem reticular formation. |
