Role of adrenoreceptors in the activation of the hypothalamo-hypophyseo-testicular complex of mice elicited by the presence of the female

Abstract

The initial components of the sexual behavior of the male is its motivation, determined by the presence of a receptive female even without direct contact with her. The stimulation, dependent upon the genotype, of the hypothaiamo-hypophyseo-testicular complex takes place in male mice under such conditions [2]. The results we have previously obtained [I] have provided a basis for the conclusion that adrenergic mechanisms participate in the regulatio n of the endocrine function of the testes during sexual motivation, that the activating influences are realized through the a-adrenoreceptors, and the inhibiting influences are realized through the ~-adrenoreceptors. However it is known at the present time that both the a-, and the ~-adrenoreceptors are represented by functionally different subtypes: el, a2 [4,5] and 91, ~2 [4,14]. Which of the subtypes of the adrenoreceptors participate in the regulation of the hypothalamo-hypophyseo-testicular complex during sexual activation elicited by the presence of a receptive female remain unknown. At the same time this problem is important for the understanding of the mechanisms of the regulation of the endocrine function of the testes, as well as for the prospects for the possibile pharmacological correction of pathologically expressed sexual motivation. The elucidation of the role of the individual subtypes of the adrenoreceptors in sexual activation elicited only in the presence of a receptive female was in fact the goal of the present study. MATERIALS AND METHODSThe experiment was carried out in male mice of two hybrid lines, CBA/Lac and A/He at the age of 2.5-3.0 months. The animals were born and raised in the Institute's vivarium in natural illumination. Food and water were obtained without limitations.Five days before the experiment the mice were placed in separate cages divided by a mesh barrier into two halves, and were trained to the hand for ten minutes daily. After five days a female of the BALB/c line, in estrus elicited by the successive administration of estradiol and progesterone, was presented to each male for 40 min in the free half of the cage. Adrenobiockers which exerted an effect primarily on one of the four subtypes of adrenoreceptors were used in the experiments: prazosin, which blocks ~i-[6], yohimbine, which blocks a 2-[12], metoprolol, which blocks 81-[I0], and optimol, which blocks the 82-adrenoreceptors [Ii], were used in the experiments. The prazosin and the yohimbine were dissolved in 0.04 ml of glacial acid immediately before administration, and were diluted to the necessary concentration with equal volumes of twice-distilled water and physiological solution. The metoprolol and the optimol were dissolved in physiological solution. All the preparations were administered subcutaneously in a volume of 0.i ml of the appropriate solvent, which was also used for the administration to the control animals, 30 min prior to the presentation of the female. Those doses of the adrenoblockers which did not exert a substantial influence on the initial level of ...

The Role of the Immune System in Behavioral Strategies of Reproduction

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