Cortical control of nociceptive transmission from the heart

Depriming effect of the cerebral cortex (predominantly of zones 1 and 2 of viscerosomatic sensitivity) on transmission of the cardiac afferent signals with a subcortical nociceptive component, which were provoked by electrical stimulation of the sinoatrial node of the heart conduction system, was established in experiments on cats. The agonist of opiate M-receptors morphine considerably potentiated the effect of cortical stimulation, while opiate receptor blocker naloxone antagonized it.