The effect of lactic acid on intracellular pH and adenosine output from superfused rat soleus muscle fibres.
We investigated the effects of graded doses of lactic acid on the intracellular pH and adenosine output from superfused bundles of about 15 skeletal muscle fibres. Intracellular pH was determined using the fluorescent intracellular dye, 2',7'-bis-(2-carboxyethyl)-5-(and,6-) carboxyfluorescein (BCECF), and adenosine efflux was measured by HPLC. Intracellular pH was 7.07 +/- 0.05 under control conditions, which was around 0.35 units lower than extracellular pH, and adenosine output was 63 +/- 10 pmol/min/g. Lactic acid produced dose-dependent decreases in intracellular pH and dose-dependent increases in adenosine output: 10 mM lactic acid decreased intracellular pH to 6.57 +/- 0.04 and increased adenosine output to 159 +/- 34 pmol/min/g. The adenosine output and the intracellular pH were well correlated (r2 = 0.988; P < 0.01).
Mo
F M
FM
Department of Physiology, The University of Hong Kong, People's Republic of China.
Ballard
H J
HJ
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D002021:Buffers; D002245:Carbon Dioxide / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000494:pharmacology*; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000187:drug effects* / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010313:Partial Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley
D002021:Buffers; D005452:Fluoresceins; D005456:Fluorescent Dyes; D002245:Carbon Dioxide; D019344:Lactic Acid; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D000241:Adenosine; D010100:Oxygen