Dissociation between heart rate and sympathetic nerve responses to baroreceptor activation in spontaneously hypertensive rats.
We tested the baroreflex in conscious, stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto controls (WKY) with incremental bolus injections of nitroprusside and methoxamine. The change in heart rate (HR) per change in mean blood pressure (MAP) was greater in WKY than in SHRSP. In contrast, the change in splanchnic nerve activity (SpNA) per change in MAP was greater in SHRSP than in WKY. The sympathetic outflow in SHRSP seems more reactive to blood pressure changes than in WKY. The discordance in HR and SpNA changes suggests that the integration of autonomic function in SHRSP is impaired.
Unger
T
T
German Institute for High Blood Pressure Research, Heidelberg, F.R.G.
Demmert
G
G
Rohmeiss
P
P
Veelken
R
R
Luft
F C
FC
D000818:Animals; D001794:Blood Pressure; D006339:Heart Rate; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D011311:Pressoreceptors / Q000378:metabolism*; D051381:Rats; D011921:Rats, Inbred WKY; D013153:Splanchnic Nerves / Q000378:metabolism*
D009599:Nitroprusside; D008729:Methoxamine