Hypothalamic paraventricular nucleus lesions decrease pressor responses to subfornical organ stimulation.

Electrical stimulation of the subfornical organ (SFO) in urethane anesthetized male Sprague-Dawley rats was associated with intensity and frequency dependent increases in arterial blood pressure. Stimulation in the hypothalamic paraventricular nucleus (PVN) also evoked increases in arterial blood pressure. Electrolytic lesions of the PVN significantly reduced SFO induced pressor responses, suggesting that the PVN constitutes part of the efferent pathways through which SFO stimulation elicits increases in blood pressure.