Extracellular acidosis results in higher intracellular acidosis and greater contraction in spontaneously hypertensive rat aorta.
Acidic pH induces a contraction in aorta from spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. The contractile response to acidic pH in SHR aorta is greater than that in WKY aorta. The purpose of this study was to investigate the correlation among extracellular pH (pH(o)), intracellular pH (pH(i)) and contraction in order to understand the exaggerated contractile response to acidic pH in SHR aorta. pH(i) measurement showed that at pH(o) 6.5, intracellular acidification was greater in SHR aorta than in WKY aorta. Decreasing pH(o) further to 6.2 in WKY aorta produced intracellular acidification close to that achieved at pH(o) 6.5 in SHR aorta, and at this level, the difference in contractile response between the two strains was also abolished. These results suggest that acidic pH(i), but not pH(o), is closely correlated with the contractile response and that the exaggerated contractile response in SHR aorta is due to a greater fall in pH(i).
Rohra
Dileep Kumar
DK
Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Saito
Shin-ya
SY
Ohizumi
Yasushi
Y
D000818:Animals; D001011:Aorta / Q000502:physiology / Q000503:physiopathology*; D005452:Fluoresceins / Q000737:chemistry; D005470:Fluorometry / Q000379:methods; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013997:Time Factors; D014661:Vasoconstriction / Q000502:physiology*
D005452:Fluoresceins; C057433:2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester