Neurochemical correlates of sexual exhaustion and recovery as assessed by in vivo microdialysis

• Published in: Brain research 1995-03, Vol.675 (1), p.13-19
• Main Authors: Mas, Manuel, Fumero, Blas, Fernandez-Vera, Juan Ramón, Gonzalez-Mora, Jose Luis
• Format: Article
• Language: English
• Subjects: 3,4-Dihydroxyphenylacetic Acid - metabolism; 5-Hydroxyindoleacetic acid; Animals; Behavioral psychophysiology; Biological and medical sciences; Brain Chemistry - physiology; Chromatography, High Pressure Liquid; Copulation - physiology; Dihydroxyphenylacetic acid; Dopamine; Dopamine - metabolism; Ejaculation - physiology; Extracellular Space - metabolism; Fundamental and applied biological sciences. Psychology; Homovanillic acid; Homovanillic Acid - metabolism; Hydroxyindoleacetic Acid - metabolism; Male; Masculine sexual behavior; Medial preoptic area; Microdialysis; Neurotransmission and behavior; Preoptic Area - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Sprague-Dawley; Satiety Response - physiology; Serotonin - metabolism; Sexual Behavior, Animal - physiology; Sexual exhaustion
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/0006-8993(95)00029-P

The extracellular levels of the dopamine (DA) metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the medial preoptic area (MPOA) of male rats were monintored during unrestricted copulation, the ensuing state of sexual refractoriness and the resumption of mating activity. MPOA dialysates were collected from the same animal during four consecutive days. In the first day the subjects were allowed to copulate until reaching a satiation criterion. That was associated with a marked increase in the dialysate levels of the three metabolites assessed. During the next two days the animals remained sexually inactive when exposed to receptive females. Their basal levels of DOPAC and HVA were elevated, whereas those of 5-HIAA remained as low as in the first session. During the non-mating exposure to receptive females there were only minor changes in the three metabolites. By the fourth day, just before the animals resumed copulation, the basal levels of the DA metabolites, especially HVA, had decreased to values closer to those found in the first day. When they mated again to exhaustion the levels of DOPAC, HVA, and 5-HIAA increased as in the first session. The neurochemical changes found during the intervening state of sexual inactivity (i.e. increased levels of DA metabolites) are reminiscent of the effects of DA receptor blockers, which suggests a possible neurochemical mechanism for sexual refractoriness.