Vagus nerve mediates the increase in estrogen receptors in the hypothalamic paraventricular nucleus and nucleus of the solitary tract during fasting in ovariectomized rats.

The effect of total subdiaphragmatic vagotomy on estrogen-receptor immunoreactivity (ERIR) in the paraventricular nucleus (PVN) and nucleus of the solitary tract (NTS) was examined in fasted ovariectomized rats to clarify the peripheral inputs mediating fasting-induced increase in ERIR in these two nuclei. Vagotomy abolished the effect of 48-h fasting on the expression of ER in these two areas. The result indicates that the neural signal(s) that increase the expression of ER in the PVN and A2 region of the NTS following 48-h fasting is transmitted through the vagus. The involvement of the vagus in the fasting-induced increase in ER in the PVN and A2 region may also be the same neural pathway involved in the suppression of pulsatile luteinizing hormone secretion in fasted female rats.