Influence of food deprivation on sympathetic support of blood pressure in the spontaneously hypertensive rat
J. Mark Van Ness: https://orcid.org/0000-0001-5902-8735
Health, Exercise, and Sport Sciences Department
We examined the effects of short-term food deprivation on directly measured blood pressure and sympathetic support of blood pressure in male (n=7, 231±7 g) and female (n=9, 193±4 g) spontaneously hypertensive rats (SHR, Charles River). Carotid arterial catheters were inserted under halothane anesthesia for direct assessment of cardiovascular function in conscious, unrestrained rats. After several days of recovery, mean arterial blood pressure (MAP) and heart rate (HR) were determined prior to, during, and after food deprivation. Baseline MAP and HR were 170±14 mmHg and 351±13 beats/min in males and 187±6 mmHg and 354±9 beats/min in females. An overnight fast produced significant (P<0.05) reductions in MAP and HR. After 48-hours of food deprivation, MAP was markedly reduced in males (−42±7 mmHg) and in females (−42±9 mmHg). Heart rate was significantly decreased during fasting in both males (−76±10 beats/min) and females (−60±11 beats/min). Caloric deprivation was accompanied by a significant reduction in sympathetic support of blood pressure (−32±8 mmHg in males, −21±7 mmHg in females) as determined by the depressor response to ganglionic blockade produced by hexamethonium/atropine (30.0/0.1 mg/kg). After three days of refeeding, MAP, HR, and sympathetic support of blood pressure returned to values not significantly different from baseline. The results suggest that short-term food deprivation produces rapid reductions in MAP and HR in the SHR, which are mediated, at least in part, by reduced sympathetic tone.
Jones, M. A.,
Van Ness, J. M.,
Casto, R. M.,
Overton, J. M.
Influence of food deprivation on sympathetic support of blood pressure in the spontaneously hypertensive rat.
Nutrition Research, 18, 1581–1594.