[Effect of leucine-enkephalin on the neuronal activity of the cerebral cortex]

In the experiments on non-anesthetised, flaxedilimmobilized rats it has been shown that the injection of leucin-enkephalin (150 micrograms) into the lateral ventricle of the rat brain induces different changes in the activity of 21 test neurons of the sensomotor zone of the brain cortex. Spike discharges of 5 neurons decreased, while those of 11 neurons increased. Naloxone (2 mg/kg, i. v.) completely prevented both inhibiting and activating effects of leucin-enkephalin after repeated injections of this pentapeptide. Leucin-enkephalin failed to change the activity of 5 neurons.