CHRONIC INTRACEREBRAL INFUSIONS OF VASOPRESSIN AND VASOPRESSIN ANTAGONIST MODULATE BEHAVIORAL-EFFECTS OF INTERLEUKIN-1 IN RAT

To assess the role of sex dependent brain vasopressinergic transmission in the modulation of the neural effects of interleukin-1, castrated male rats that are deficient in vasopressin were implanted intracerebroventricularly with an Accurel collodion mini device containing 10 mug AVP whereas intact male rats were implanted with a similar device containing 50 mug of dPTyr(Me)AVP, a specific antagonist of the vasopressor-like receptors of vasopressin. Control rats in each sex group were implanted with an Accurel device containing distilled water. Acute intraoerebroventricular injection of 1.25-2.50 ng recombinant human interleukin-1beta decreased in a dose and time-dependent manner social investigation of a juvenile conspecific. This effect was more intense in intact rats chronically infused with dPTyr(Me)AVP and less intense in castrates infused with AVP. These results confirm the modulatory role of sex-dependent vasopressinergic neurotransmission on the neural effects of interleukin-1.