RELEASE OF ACETYLCHOLINE FROM THE HIPPOCAMPUS OF FREELY MOVING RATS DURING SENSORY STIMULATION AND RUNNING

The release of acetylcholine (ACh) from the dorsal hippocampus and sensorimotor cortex was measured during sensory stimulation and motor behavior in freely moving rats and under urethane anesthesia. Released ACh was collected by means of a constant perfusion apparatus. There was a significant increase in ACh release from the hippocampus during sensory stimulation and running but the cortical release was not significantly changed. Systemic administration of atropine sulfate did not change the increase in hippocampal release due to sensory stimulation and motor activity in freely moving rats, but it blocked the increase in ACh release due to sensory stimulation under urethane anesthesia. Both acute and chronic septal lesions abolished the increase of ACh due to sensory stimulation and running and the chronic lesions also reduced the resting release of ACh from the hippocampus. Results show that both sensory and motor behavior activates the septo-hippocampal cholinergic tract but only the activation resulting from sensory stimulation is abolished by atropine. This suggests that different pathways activate the septum during sensory stimulation and motor activity. © 1979.