Does interferon exert its actions through opiate receptors.

It had been reported that alpha interferon (alpha-IFN) induces endorphin-like effects such as analgesia and catatonia. These effects, reversed and prevented by naloxone, suggest that the alpha-IFN effect is mediated via opiate receptors. In order to examine this hypothesis, the present study was initiated. Extracellular cortical cell recording and microiontophoretic application of alpha-IFN, morphine, and naloxone, as well as the application of these three drugs on the coaxially stimulated guinea-pig ileum preparation were used. alpha-IFN application induced excitation in cortical cells and on the guinea-pig ileum. In contrast, the main effect elicited by morphine was a decrease in both preparations. Naloxone was able to reverse and/or prevent the morphine effects in both preparations, but failed to alter the effects induced by alpha-IFN. The present observations using the guinea-pig ileum preparation and cortical neurons recording failed to support the hypothesis that alpha-IFN effects are mediated via opiate receptors.