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 studies. Since CRF is thought to be involved in emotional state of the brain, the present study was undertaken to follow the possible alterations in corticotropin-releasing factor-like immunoreactivity (CRF-LI) in different 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 nonsignificant CRF-LI enhancement. In the basal forebrain, the CRF-LI decreased. These results suggest that ANP(1-28) may moderate activation of the CRF-ergic system in the brain which could be related to the neuroendocrine and behavioral action.