Blood pressure and heart rate responses to intracerebroventricular infusion of sodium chloride solution in normotensive and hypertensive rats.
An increased central salt sensitivity is thought to be basically involved in hypertension. Therefore, in anaesthetized normotensive (Wistar, WKY) and hypertensive (SHR) rats, small amounts (10 microliters in 20 min) of both isotonic and hypertonic NaCl solutions (0.154 M, 0.3 M, 0.6 M and 1.0 M) were i.c.v. applied and blood pressure (BP) and heart rate (HR) responses registered. Central administration of hypertonic NaCl solution caused an elevation in BP and HR in both strains. The response magnitude was positively correlated to the NaCl concentration used. This increase could be interrupted by i.v. injection of a ganglionic blocker (tetraethylammoniumbromide). Despite of differences in time course, the magnitude of the BP and HR increases were much more elevated in SHR and WKY than in Wistar rats, suggesting strain differences. Considering the results obtained with 1.0 M NaCl solution, the following values were reached: in Wistar: delta syst. BP +15.7 mm Hg, delta HR +23.3 bpm; in WKY: delta syst. BP +40.2 mm Hg, delta HR +51.6 bpm; in SHR: delta syst. BP +46.0 mm Hg, delta HR +48.0 bpm. On the contrary, isotonic NaCl solution, when centrally applied, caused an elevation in HR (+25 bpm) and BP (delta syst. BP +6.2 mm Hg) only in SHR. These results support the idea that an exaggerated central sensitivity to sodium chloride may participate in hypertension.
Physiological Institute, School of Medicine, Magdeburg, G.D.R.
E
E
Appenrodt
A
A
Brattström
V
V
Moritz
W
W
Schälike
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006973:Hypertension / Q000503:physiopathology*; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology*; D013045:Species Specificity
D012965:Sodium Chloride