Lordosis facilitation by LHRH, PGE2 or db-cAMP requires activation of the kinase A signaling pathway in estrogen primed rats.

Dose-response curves for lordosis and proceptive behaviors were obtained for luteinizing hormone releasing hormone (LHRH), prostaglandin E2 (PGE2) and dibutyryl cyclic AMP (db-cAMP), by infusing them in the right lateral ventricle (i.c.v.) of ovariectomized (OVX) estradiol benzoate (E2B; 2 microg) treated rats. Two dose levels, one producing the maximal effect and the other one producing a submaximal response (approximately ED50) were selected for testing the capacity of Rp-cAMPS, a kinase A blocker, to modify the behavioral response to the three compounds. I.c.v. injections of Rp-cAMPS, significantly depressed both lordosis and proceptive responses induced by LHRH, PGE2 and db-cAMP. The results show that these agents use the cAMP-kinase A signaling pathway to elicit their stimulating effect on estrous behavior in the rat.