Peripheral sensory stimulation and the release of transmitter amino acids in vivo from specific regions of cerebral cortex.

Abstract

The effects of sensory stimulation on the release of amino acids from sensori-motor and visual cortices have been studied using a superfusion technique. Electrical stimulation of the brachial plexus contra-lateral to the superfusion cannula increased significantly the release of glutamate and glutamine from the sensori-motor cortex of anesthetized rats. No clear effect was observed with the other amino acids. Stimulation of the ipsi-lateral plexus had no effect on glutamate and glutamine release. In unanesthetized animals, stimulation of the contra-lateral brachial plexus raised the levels of all the amino acids in sensori-motor cortex superfusate. Weak photic stimulation of the eyes of dark-adapted rats increased glutamate release from the visual cortex but caused no significant change in the release of other amino acids. All evoked increases in amino acid release were reversible at the cessation of the stimuli.