Untreated spontaneously hypertensive rats exhibited decreased sensitivity of reflex control of renal sympathetic nerve activity (-1.78 vs -3.62 %/mm Hg, p<0.01) compared with Wistar-Kyoto rats.
Do antihypertensive agents (trichlormethiazide, atenolol, nicardipine, enalapril) affect arterial baroreceptor reflex control of renal sympathetic nerve activity and heart rate in conscious spontaneously hypertensive rats?
In a rat model, spontaneously hypertensive rats show decreased baroreceptor reflex sensitivity compared to normotensive controls, while various antihypertensive agents similarly reduce blood pressure.
The effects of antihypertensive treatment with four currently used agents (trichlormethiazide, atenolol, nicardipine, and enalapril) on the arterial baroreceptor reflex control of renal sympathetic nerve activity and heart rate were investigated in 45 conscious spontaneously hypertensive rats and 37 age-matched Wistar-Kyoto rats. Antihypertensive agents were administered for 2 weeks beginning at 8 weeks of age to treat and prevent the development of hypertension. Blood pressure was reduced to a similar level (-13 +/- 3 mm Hg, p < 0.05) by each antihypertensive agent. Blood pressure, heart rate, and renal sympathetic nerve activity were recorded in the conscious state during phenylephrine and nitroglycerin ramp infusion. The gain in the baroreceptor reflex was determined from the maximum slope of logistic function curves. Untreated spontaneously hypertensive rats exhibited decreased sensitivity of reflex control of renal sympathetic nerve activity and heart rate (-1.78 +/- 0.07% of control/mm Hg and -2.16 +/- 0.05 beats per minute/mm Hg, respectively) compared with untreated Wistar-Kyoto rats (-3.62 +/- 0.18% of control/mm Hg, p < 0.01, and -3.46 +/- 0.11 beats per minute/mm Hg, p < 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Kumagai et al. (Sun,) conducted a other in Hypertension (n=82). Antihypertensive agents (trichlormethiazide, atenolol, nicardipine, and enalapril) vs. Untreated rats was evaluated on Arterial baroreceptor reflex control of renal sympathetic nerve activity and heart rate. Untreated spontaneously hypertensive rats exhibited decreased sensitivity of reflex control of renal sympathetic nerve activity (-1.78 vs -3.62 %/mm Hg, p<0.01) compared with Wistar-Kyoto rats.