NERVE GROWTH-FACTOR AFFECTS DEFENSE-RELATED BEHAVIORS, BUT NOT LORDOSIS, IN OVARIECTOMIZED, ESTROGEN-TREATED RATS

Effects of NGF and anti-NGF on estrogen-sensitive behaviors were exami ned in ovariectomized, estrogen-treated rats. Intracerebroventricular (i.c.v.) administration of NGF resulted in a significant decrease in b ody weight. Daily treatment with low levels of estradiol resulted in a steady increase in lordosis behavior as reflected by average lordosis quotient and lordosis score. No effects of NGF or anti-NGF on lordosi s behavior were detected. Estrogen treatment also resulted in a signif icant increase in the number of vocalizations elicited from female con trols by male contact during sex behavior. NGF-treatment enhanced this effect, resulting in significantly more vocalizations elicited earlie r in the course of estrogen treatment than were elicited from non-NGF- treated controls. These effects were blocked by progesterone. An incre ase in the number of rejections elicited by male contact during sex be havior was also observed in NGF-treated animals relative to controls. In addition, i.c.v. infusions of anti-NGF prevented the estrogen-media ted increase in elicited vocalizations, suggesting that NGF may have a physiological role in regulating this behavior. These data implicate NGF in the regulation of specific defense-related behaviors in estroge n-treated rats. Effects of NGF and anti-NGF on immunocytochemical stai ning for p75NGFR- and ChAT-like immunoreactivity were also analyzed an d are discussed.