title: An investigation of intrinsic buffering power in rat vascular smooth muscle cells.
abstract: Intrinsic buffering power (beta i) has been measured in vascular strips and single cells from rat mesenteric artery. Intracellular pH (pHi) regulation was inhibited to prevent overestimation of beta i due to acid extrusion or entry via regulatory processes. At resting values of pHi (7.0-7.2), a mean value of 41 +/- 4 mM/pH unit for beta i was found. beta i increased approximately fivefold from 30 to 150 mM/pH unit over the pHi range 7.5-6.5. The mean data relating beta i to pHi could be described by relating beta i to buffer concentrations and pKa. This gave a value of 310 mM for buffer concentration and a pKa of 6.0. As changes in pHi are known to have marked effects on vascular tone then the increase in beta i as pHi falls may be considered as a means of attenuating pHi decreases, before pH regulation restores pHi to resting levels.
authors.affiliation: Physiological Laboratory, University of Liverpool, UK.
authors.forename: C
authors.initials: C
authors.lastname: Austin
authors.forename: S
authors.initials: S
authors.lastname: Wray
mesh_terms: D000818:Animals; D001578:Benzopyrans; D002021:Buffers; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D008744:Methylamines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000737:chemistry* / Q000166:cytology / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001578:Benzopyrans; D002021:Buffers; D002087:Butyrates; D005456:Fluorescent Dyes; D008744:Methylamines; C063917:SNARF dye; D020148:Butyric Acid; C023336:trimethylamine