Food restriction attenuates the blood pressure response to PVN lesions in aortic coarctation hypertension

The purpose of this study was to examine the role of the paraventricular hypothalamic nucleus (PVN) in neural support of blood pressure (BP) in food restricted and ad libitum fed aortic coarctation-induced hypertensive rats. Suprarenal aortic coarctation (AC) was performed in male Sprague-Dawley rats (Charles River, 225-250g). One week later rats were assigned to control (ADLIB) and food restricted (FR) groups (60% of ADLIB consumption) for 3 weeks. Resting BP, heart rate (HR) and the BP response to ganglionic blockade (ΔBP;GB hexamethonium/atropine) was obtained in conscious, catheterized rats the day before, and three days after bilateral electrolytic lesions (I mA 15 seconds) of the PVN (PVNx) or sham operations. Data below (mean ± SEM) were obtained 3 days post PVNx or sham: ADLIB FR Sham PVNx Sham PVNx BP(mmHg) 156 ± 11 103 ± 13*119 ± 4a 100 ± 4*HR(bpm) 345 ± 9 343 ± 17 298 ± 8a 323 ± 12 ΔBP; GB -64 ± 8 -29 ± 4*-43 ± 3a -27 ± 6**indicates P\u3c0.05 vs respective SHAM a indicates P\u3c0.05 vs ADLIB These results indicate: 1) FR reduces resting BP 2) PVN lesions reduce BP and sympathetic support of BP in AC hypertensive rats, and 3) FR rats have less of a reduction in BP and neural support of BP after PVN lesions. These findings suggest that reductions in BP with food restriction may be mediated by alterations in hypothalamic control of autonomic function