Recovery of masculine copulatory behavior from lesions of the medial preoptic area: effects of age versus hormonal state.
The present experiments tested the hypothesis that one consequence of the hormonal activation of the onset of copulation in male rats is a reduction in the plasticity of the medial preoptic area (MPOA) with respect to its role in copulation. In Experiment 1, one group of male rats received 1 mg of testosterone propionate daily from 10 to 45 days of age, and a second group received oil injections. Males in each of these groups received either bilateral MPOA lesions (MPOAX) or a sham operation as juveniles (28-31 days of age). The proportions of MPOAX males copulating as adults did not differ for males previously injected with oil or testosterone. In Experiment 2, male rats were castrated at 15 days of age. These castrated males as well as gonadally intact males received bilateral MPOA lesions or a sham operation in adulthood. Following testosterone replacement, MPOAX males displayed copulatory impairments regardless of hormonal state during development. Taken together, the results of these experiments suggest that the plasticity (with respect to copulation) of the neural system encompassing the MPOA is a function of some aspect of chronological age unrelated to the animal's developmental hormonal condition prior to the time of the lesion.
D000367:Age Factors; D000818:Animals; D001931:Brain Mapping; D002369:Castration; D003307:Copulation / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004542:Ejaculation / Q000187:drug effects; D008297:Male; D009473:Neuronal Plasticity; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D012741:Sexual Maturation / Q000187:drug effects; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone