ALPHA-INTERFERON MODIFIES CORTICAL EEG ACTIVITY - DOSE-DEPENDENCE AND ANTAGONISM BY NALOXONE

Activation of the immune system is believed to provide signals in the form of chemical messengers that are able to change neural activity in a variety of regions of the central nervous system. In studies designed to examine the effects of alpha-interferon (alpha-IFN) upon the central nervous system, recordings of cortical EEG were made following intracerebroventricular injection of various doses of the cytokine. Administration of 25 U of alpha-IFN increased the amount of wake and decreased the amount of desynchronized sleep in the first hour following injection; an increase in synchronization being seen in the third hour. alpha-IFN at 250 U increased the amount of synchronization and decreased the amount of desynchronized sleep in the EEG, principally in the second hour, with 2500 U having similar but more potent effects, mostly in the first hour. The (-mu) opiate receptor antagonist, naloxone, was found to decrease the amount of EEG synchronization and blocked the increases in synchronized sleep produced by 250 U alpha-IFN. The data suggest that interferon on increases EEG synchronization in a dose-dependent and specific manner, probably via central-mu-opiate receptors. The increased wake in the EEG following 25 U suggests, however, that another discrete effect of alpha-IFN may also exist.