THE EFFECTS OF ATRIAL-NATRIURETIC-PEPTIDE (ANP(1-28)) ON CORTICOTROPIN-RELEASING FACTOR IN BRAIN OF RATS

We have shown that ANP has anxiolytic-like effects in behavioral studi es. Since CRF is thought to be involved in emotional state of the brai n, the present study was undertaken to follow the possible alterations in corticotropin-releasing factor-like immunoreactivity (CRF-LI) in d ifferent regions of the brain in rats following ANP treatment. CRF-LI immunoreactivity was determined in hypothalamic and extrahypothalamic brain areas after central injection of atrial natriuretic peptide 1-28 (ANP(1-28)) in rats. After various doses of ANP(1-28) administration the CRF-LI significantly increased in the hypothalamus,the hippocampus and the frontal cortex. In the amygdala, ANP caused a marked but nons ignificant CRF-LI enhancement. In the basal forebrain, the CRF-LI decr eased. These results suggest that ANP(1-28) may moderate activation of the CRF-ergic system in the brain which could be related to the neuro endocrine and behavioral action.