title: Application of high-field 1H-NMR spectroscopy for the study of perifused amphibian and excised mammalian muscles.
abstract: Frog sartorius and gastrocnemius muscles were perifused at 20 degrees C, the intracellular pH (pHi) and the concentration of phosphocreatine were determined in the resting muscle by 1H-NMR spectroscopy at 470 MHz; values of pHi = 7.31 +/- 0.05 (n = 7) and concentration of phosphocreatine = 20.4 +/- 1.1 mumol/g wet wt. (n = 6) were found. The hydrolysis of phosphocreatine and the simultaneous increase in lactate upon perifusion with 10 mM caffeine (in Ringer's solution) was followed with a time resolution of 1 min. Lactate increased at a rate of 1.0 mumol/g per min, but no pHi change was recorded during the time monitored. The lower limit for the buffering capacity of the muscle cytosol was estimated to be 16.7 mumol/g muscle per pH unit from the uncertainty in pHi determination (+/- 0.03 pH units) and from the amount of lactate produced and phosphocreatine hydrolyzed. Changes in pHi, lactate concentration and fatty acyl chain intensity were monitored by 1H-NMR spectroscopy at 361 MHz in ischemic rat skeletal muscle, excised and stored at 20 degrees C. The resonances in the 1H-NMR spectrum of a human skeletal muscle perchloric acid extract are reported and tentatively assigned.
mesh_terms: D000818:Animals; D000861:Anserine / Q000032:analysis; D002110:Caffeine / Q000494:pharmacology; D003600:Cytosol / Q000032:analysis; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000096:biosynthesis; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000032:analysis* / Q000187:drug effects; D010477:Perfusion; D010725:Phosphocreatine / Q000032:analysis; D011894:Rana pipiens; D051381:Rats
chemical_list: D007773:Lactates; D010725:Phosphocreatine; D002110:Caffeine; D000861:Anserine