Effect of lesions of the anteroventral third ventricle (AV3V) on the development of hypertension in spontaneously hypertensive rats.

Lesions of the anteroventral third ventricle (AV3V), an angiotensin and osmosensitive region of the anterior hypothalamus, prevent or abort hypertension in a number of rat models. To determine if AV3V lesions alter hypertension in spontaneously hypertensive rats (SHR), lesions and control sham lesions were made in young SHR at 28 days of age. AV3V lesions had no effect on the development of hypertension in SHR. However, lesioned rats demonstrated significantly reduced pressor responses to intracerebroventricular injections of angiotensin II (AII) and hypertonic NaCl, and drinking produced by centrally administered AII. The depressor effect of central AII receptor blockade was also significantly attenuated in lesioned SHR. These effects appeared to be of central origin since the lesion did not affect the pressor action of intravenous AII or norepinephrine (NE). It is concluded that unlike other models of experimental hypertension (steroid-salt, one-and two-kidney renal, neurogenic) the development of hypertension in SHR does not depend upon the integrity of the AV3V region.