Area postrema: Abrupt EEG synchronization following close intra-arterial perfusion with serotonin

Abstract

The infusion of minute amounts of serotonin into the arterial circulation of the area postrema and adjacent medulla resulted promptly in low frequency shifts in the EEG. The low frequency shifts we observed are highly reminiscent of those reported to occur at the onset of slow-wave sleep in the unanesthetized animal. Infusion of similar concentrations of serotonin via other routes of administration did not produce the consistent low frequency shifts obtained by postremal perfusion. In contrast norepinephrine, another monoamine, produced a desynchronization of the EEG when infused into the postremal circulation. Acetylcholine and lactic acid were without effect under the conditions of our experiments.