Immune response products alter CNS activity: interferon modulates central opioid functions

The present report provides evidence to support the hypothesis that peptides released during an immune response alter CNS activity and thus may provide a means for the immune system to transmit afferent signals into the brain. Specifically, it is demonstrated that recombinant interferon-alpha (rIFN-alpha), a peptide associated with the immune response to viral infection, can alter opiate withdrawal severity in a dose-dependent manner upon direct injection into brain areas essential for this phenomenon. These results are compared and contrasted with the effect of systemically injected rIFN-alpha upon opiate withdrawal. In addition, an electrophysiological investigation into the basis of the interaction of opioids and rIFN-alpha in brain structures essential for the expression of opioid activities is also presented. Finally, the effects of rIFN-alpha upon the functions of both the CNS and other systems is discussed in terms of the effects reported for other peptides associated with immune responses.