AJP - Heart and Circulatory Physiology, Vol 251, Issue 6 1276-H1282, Copyright © 1986 by American Physiological Society
Genetic basis for altered vascular responses to ouabain and potassium-free solution in hypertension
C. A. Bruner, J. H. Myers, C. F. Sing, P. T. Jokelainen and R. C. Webb
Many properties intrinsic to vascular smooth muscle are altered in
hypertension. It is unknown whether these abnormalities are primary traits
that may contribute to the etiology of hypertension or whether these
vascular differences between the hypertensive and normotensive strains are
inherited independently of genetic factors that predispose to hypertension.
To determine if genetic factors responsible for the predisposition for
hypertension may be the same as or linked to genetic factors determining a
specific vascular response, adult stroke-prone spontaneously hypertensive
rats (SHRSP), normotensive Wistar-Kyoto (WKY) rats, and progeny of genetic
crosses of SHRSP and WKY rats (F1, F2, F1 X WKY, F1 X SHRSP) were studied.
Rats were killed and helical aortic strips were mounted in a tissue bath
for isometric force recording. Contractile responses to 10(-3) M ouabain
(expressed as a percent of force generated to a maximal depolarizing
stimulus) were greater in aortas from SHRSP (90 +/- 9%) compared with
aortas from WKY rats (38 +/- 5%, P less than 0.05). The half time for
contraction in K+-free solution was more rapid in aortas from SHRSP (21 +/-
4 min) when compared with aortas from WKY rats (48 +/- 4 min, P less than
0.05). A significant positive correlation between blood pressure (tail-cuff
method) and the contractile response to 10(-3) M ouabain was observed in
the segregating F2 progeny. In contrast, no correlation between blood
pressure and the half time for contraction in K+-free solution was observed
in the segregating F2 progeny.(ABSTRACT TRUNCATED AT 250 WORDS)
