HUMAN RECOMBINANT INTERFERON-ALPHA INHIBITS NALOXONE BINDING TO RAT-BRAIN MEMBRANES

Regulation of certain central nervous system (CNS) functions by the immune system may involve interferons (IFNs) acting through opioid receptors. Human recombinant interferon alpha (hrIFN-alpha), as well as natural IFN-alpha, have been reported to modulate a variety of physiological CNS functions both in vivo and in vitro. If the mechanism is via opioid receptors then IFN-alpha should inhibit the binding of certain opioid radioligands to brain membranes. This study reports the inhibitory effect of hrlFN-alpha on the binding of H-3-naloxone to rat brain membranes in vitro. The inhibitory effect at 37-degrees-C is hrIFN-alpha concentration dependent over the range of 500 to 6000 antiviral units per ml (U/ml) with 500-mu-g of membrane protein. The presence of NaCl (100mM) increases specific binding of naloxone and attenuates the inhibitory effect of hrIFN-alpha. The inhibitory effect of hrIFN-alpha is sensitive to temperature with maximum inhibition observed at 37-degrees-C, and less as incubation temperature is reduced. These data suggest that IFN-alpha may modulate certain physiologic functions via opioid pathways in the brain.