Temporal Coincidence between the Excitation of Ventromedial Hypothalamic Efferents and the Induction of Lordosis Reflex in Ovariectomized Estrogen-Primed Rats

Endocrine Journal

SHIGERU TASHIRO¹  YASUHIKO KONDO¹  YASUO SAKUMA¹ 

[1] Department of Physiology, Nippon Medical School

关键词: Sexual behavior;    Antidromic action potential;    Neuronal excitability;   

DOI  :  10.1507/endocrj.45.519

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(49)Cited-By(4)The temporal changes in excitability in ventromedial hypothalamic neurons which project to the midbrain central gray caused by chronic estrogen exposure were measured in ovariectomized rats. In 66 urethane-anesthetized animals which had either no capsule, or had a capsule containing estrogen implanted for 24h, 48h, 72h or 96h, 189 antidromic action potentials were recorded in the ventromedial hypothalamus (VMN) in response to stimulation of the midbrain central gray (CG). The antidromic activation threshold was lower in 40 recordings made from the VMN in the 72-h or 96-h group than in 67 from the no-treatment, 24-h or 48-h group. The decrease in the threshold coincided with the emergence of the lordosis reflex. In a separate cohort of ovariectomized rats, any absence of estrogen for 2-48h before and during the measuring abolished the neuronal as well as the behavioral effects at 72h. The results suggest that the lordosis reflex induced by estrogen alone depends on the excitation of VMN efferents to the CG. In addition, the indispensability of estrogen at the time of electrophysiological and behavioral evaluation indicates that a certain direct neural action of estrogen is involved in the behavioral activation.

【 授权许可】

Unknown