Intracellular pH measured by 31P-NMR in isolated rat heart during alpha-1-adrenoceptor stimulation.
Changes of intracellular pH (pHi) after alpha-1-adrenoceptor stimulation (5 x 10(-5) mol/l phenylephrine in the presence of 10(-6) mol/l timolol) were studied in isolated perfused rat hearts by 31P-NMR spectroscopy in order to use the whole organ without disruption. The contractility was monitored simultaneously in all hearts. Alpha-1-adrenoceptor stimulation gave an alkalinization by 0.02 +/- 0.01 pH-units (mean +/- S.E.M.) after 5 min and by 0.03 +/- 0.01 pH-units (mean +/- S.E.M.) after 15 min. Thus, an intracellular alkalinization after myocardial alpha-1-adrenoceptor stimulation was observed during close to physiological conditions. The elevation of pHi may contribute to maintain the inotropic effect after alpha-1-adrenoceptor stimulation.
Hanem
S
S
Department of Pharmacology, University of Oslo, Norway.
Grønås
T
T
Holten
T
T
Jynge
P
P
Skomedal
T
T
Osnes
J B
JB
D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects; D006321:Heart / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008954:Models, Biological; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D010477:Perfusion; D010656:Phenylephrine / Q000494:pharmacology; D010759:Phosphorus Isotopes; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000032:analysis / Q000187:drug effects / Q000502:physiology*; D013999:Timolol / Q000494:pharmacology
D010759:Phosphorus Isotopes; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D013999:Timolol