EFFECTS OF NEUROCHEMICAL LESIONS OF THE PREOPTIC AREA ON MALE SEXUAL-BEHAVIOR IN THE JAPANESE-QUAIL

Two experiments were cam out during which the noradrenergic neurotoxin , 5-amino-2,4-dihydroxy-alpha-methylphenylethylamine (5-ADMP) was appl ied to the brain of quail in order to evaluate the role of the noradre nergic system in the control of male copulatory behavior. In the first experiment, the ICV injection of 5-ADMP slightly enhanced the sexual behavior observed in testosterone (T)-treated castrated male quail. Th is brings additional support to the notion that norepinephrine tonical ly inhibits male copulatory behavior in quail. In the second experimen t, 5-ADMP implanted directly into the preoptic area disrupted the rest oration by T of copulatory behavior in castrated quail and, at the sam e time, produced a brain lesion that partly destroyed the sexually dim orphic medial preoptic nucleus, a previously established site of T act ion on behavior. These lesions produced by a high (presumably too high ) concentration of neurotoxin provided an independent confirmation of effects previously observed after electrolytic lesions. Correlation an alyses also confirmed that the medial part of the POM just rostral to the anterior commissure is more closely associated with copulatory beh avior and may, therefore, represent a key center for steroid action on this behavior.