Appetitive and Consummatory Male Sexual Behavior in Japanese Quail Are Differentially Regulated by Subregions of the Preoptic Medial Nucleus

Abstract

Central testosterone aromatization is required for the activation of both appetitive (ASB) and consummatory (CSB) male sexual behavior in Japanese quail. There are two major clusters of aromatase immunoreactive (ARO-ir) cells in the rostral forebrain; these outline the nucleus preopticus medialis (POM) and the nucleus striae terminalis (BST). We investigated the role of these nuclei in the regulation of ASB and CSB. Appetitive male sexual behavior was measured with the use of a learned social proximity procedure that quantified the time spent by a male in front of a window with a view of a female who was subsequently released into the cage, providing an opportunity for CSB. Males first acquired the response and then received bilateral electrolytic lesions aimed at the POM or BST, followed by retesting for ASB and CSB. Brain sections were stained for ARO-ir, and lesions to the two ARO-ir cell groups were quantitatively characterized. Lesions damaging the POM completely abolished CSB and also significantly decreased ASB. Lesions of the rostral BST had no effect on ASB, but moderately decreased CSB. Detailed anatomical analysis revealed that lesions of a subdivision of the POM just rostral to the anterior commissure specifically impair CSB, whereas lesions that are more rostral to this subdivision induce a severe deficit in ASB. These data indicate that different subregions of the POM regulate ASB and CSB in a somewhat independent manner, whereas the BST is only important in the regulation of CSB.

Topography in the preoptic region: Differential regulation of appetitive and consummatory male sexual behaviors

“…These responses are not expressed in castrated males and are restored to rates observed in intact sexually mature males by treatments with exogenous testosterone [6,25,29,63]. As mentioned above, effects of testosterone on these two measures of ASB require aromatization of the androgen [28,136].…”

“…[25,29,67]). In both species, the action of testosterone on ASB also seems to be mediated by its aromatization into an estrogen.…”

“…These movements are greatly facilitated in males, including sexually naive males, by the simple view of a female [125,140]. These rhythmic cloacal sphincter movements are facilitated nearly 20-fold in castrated males treated with testosterone and provided with visual access to a female as compared to castrated males receiving no testosterone [29]. These cloacal sphincter muscle movements are reminiscent of non-contact erections described in mammalian species [121] in that they involve muscle movements that control effector organs associated with consummatory aspects of male sexual behavior in response to sensory cues emitted by a female.…”

“…Investigations in rats by Barrry Everitt and his colleagues suggesting a double dissociation between brain regions controlling appetitive and consummatory sexual behavior in rats [67,68] were especially important in stimulating recent work on circuit specializations related to the control of male sexual behavior. Sophisticated behavioral tests have now been designed to analyze in a reasonably independent manner these two aspects of sexual behavior [29,62,67,110,140]. Studies on appetitive male sexual behavior in a diverse set of species are particularly important from a clinical perspective.…”

Examining a pathway for hormone mediated maternal effects – Yolk testosterone affects androgen receptor expression and endogenous testosterone production in young chicks (Gallus gallus domesticus)

“…We quantitatively studied AR mRNA expression in the preoptic area (including different nuclei in the medial and lateral preoptic area), the BnST (bed nuclei of stria terminalis), the ventral pallidum, and the lateral septum. Previous research has shown that these nuclei contain androgen receptors and are involved in social, aggressive and copulatory behaviors [4,10,15,19,46,47] and might therefore represent nuclei that are possibly involved in early chick behavior.…”