Influence of extracellular pH on intracellular pH in arterioles and skeletal muscle of spontaneously hypertensive and Wistar-Kyoto rats.
The effect of changing extracellular pH (pHo) on intracellular pH (pHi) in mesenteric arterioles of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats was investigated using the fluorescent indicator seminaphthorhodafluor c-SNARF-1 to measure pHi. Although the pHi of arterioles from WKY varied directly with pHo, that of SHR arterioles varied inversely. This abnormal pHi regulation in SHR was corrected by 50-microM 5-(N-ethylisopropyl)amiloride (EIPA). Vmax of H+ transport in response to changing extracellular Na+ was higher in SHR than in WKY, but Km did not differ. The Hill coefficient for H+ transport with respect to pH; was 1.69 in prehypertensive and 1.56 in hypertensive SHR. These results indicate that the Na+/H+ exchanger is particularly hyperactive in mesenteric arterioles of SHR.
Wimberger
P
P
University of Munich, Institute of Physiology, Germany.
Marin-Grez
M
M
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001160:Arterioles / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure; D005110:Extracellular Space / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000098:blood supply* / Q000378:metabolism*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011921:Rats, Inbred WKY; D012964:Sodium / Q000378:metabolism
D000889:Anti-Arrhythmia Agents; D000584:Amiloride; D012964:Sodium; C039614:ethylisopropylamiloride