Catecholamine histofluorescence in the median eminence of female rabbits activated by mating.

Mating was used in the rabbit as a physiological trigger, easily definable in time, for the activation of gonadotropic hypothalamic structures. Using the histochemical fluorescence technique of Falck and Hillarp, it has been attempted to determine whether, in relation to mating, clearly distinuishable and reproducible changes in histofluorescence occur in the tuberoinfundibular dopaminergic system in combination with hypothalamic hypophysiotropic hormone release. Between 20-30 min post-coitum an increase in DA turnover was noted in the external layer of the median eminence. The characteristics of this reaction were studied by administration of reserpine and alpha-methyl-paratyrosine. Immediately after coitus, a paradoxical fluorescence reactivation was observed in the median eminence in female rabbits in which tyrosine-hydroxylase activity was inhibited for 5 hours.