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Antagonists of the Protein Kinase A and Mitogen-Activated Protein Kinase Systems and of the Progestin Receptor Block the Ability of Vaginocervical/Flank-Perineal Stimulation to Induce Female Rat Sexual Behaviour

Authors


O. González-Flores, Centro de Investigación en Reproducción Animal, Apartado Postal No 62, Tlaxcala, Tlax. c.p. 90000, México (e-mail: oglezflo@hotmail.com).

Abstract

Brief vaginocervical stimulation using a glass rod (VCS) combined with manual flank-perineal stimulation (FS) rapidly (within 5 min) induced both receptive and proceptive behavioural responses to males in ovariectomised, oestrogen-primed rats. This receptive-proceptive response to males, resulting from a single brief (5-s duration) instance of manual VCS + FS, declined markedly within 4 h. However, the decline was prevented if the females were mounted by males immediately after the manual VCS + FS and 2 h later. We tested the participation of the cAMP-dependent protein kinase A system and the mitogen-activated protein kinase (MAPK) system in the response to VCS + FS by infusing either 100 ng of Rp-adenosine 3′,5′-cyclic monophosphorothiate triethylamonium salt (a protein kinase A blocker) or 3.3 μg of PD98059 (a MAPK blocker) i.c.v. 15 min prior to VCS + FS. Both inhibitors blocked the ability of VCS + FS to induce the proceptive-receptive responses to males at all testing intervals. In experiment 2, systemic administration of 5 mg of RU486 1 h before VCS + FS also blocked the ability of VCS + FS to induce the proceptive-receptive responses to males. The present findings suggest that both VCS + FS and mating stimuli provided by males release neurotransmitters and neuromodulators that trigger the protein kinase A and the MAPK signalling systems, which interact with the progestin receptor to rapidly (within 5 min) induce proceptive-receptive behaviour in females.

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