[The mediator spectrum of the action of morphine and the pentapeptide FK 33-824 on the neurons of the cerebral cortex].

Morphine and pentapeptide FK 33-824 were shown to reduce spontaneous and evoked neuronal discharges in the IInd somatosensory zone of the cortex on microiontophoretic and intravenous administration of cats. The neurons were identified by electric stimulation of thalamocortical fibers. The agents tested decreased neuronal responses to glutamate and acetylcholine. They failed to change responses to dopamine and enhanced responses to GABA. Morphine and pentapeptide FK 33-824 appeared to decrease slightly the inhibitory neuronal action of serotonin on microiontophoretic administration and increased it when injected intravenously. Beta-adrenoblocker propranolol decreased the inhibitory action of morphine and pentapeptide FK 33-824 on the cortical neurons.