We previously demonstrated that an intracerebroventricular injection of recombinant human interferon-α (rhIFN-α) reduced the cytotoxicity of splenic natural killer (NK) cells in rats and mice. In the present study, we investigated the brain sites at which rhIFN-α acts to suppress splenic NK activity in unanesthetized rats implanted unilaterally with a chronic hypothalamic cannula. A microinjection of 200 U of rhIFN-α into the medial part of the preoptic hypothalamus reduced NK activity to ~60% of control 30 min after the injection. Administration of 50 U of rhIFN-α also decreased NK activity to ~80%. The injection of 200 U of rhIFN-α into other hypothalamic areas (lateral preoptic hypothalamus, ventromedial hypothalamus, lateral hypothalamus, and paraventricular nucleus) had no effect. The medial preoptic hypothalamus-rhIFN-α-induced immunosuppression was completely blocked by splenic denervation, but not by adrenalectomy. These results suggest that IFN-α suppresses splenic NK activity predominantly through the medial preoptic hypothalamus-sympathetic pathway.
|American Journal of Physiology - Regulatory Integrative and Comparative Physiology
|Published - 1995
All Science Journal Classification (ASJC) codes
- Physiology (medical)