title: Effects of felodipine on energy turnover in the rat portal vein.
abstract: The effects of the vasodilating dihydropyridine, felodipine, on tissue concentrations of high-energy phosphates and on oxygen consumption and lactate production in the smooth muscle of the rat portal vein were investigated. Felodipine (100 nM) caused a gradual decrease in the amplitude of the spontaneous phasic contractions in a calcium-containing medium. The mean active force was reduced by about 80% within 15 min. The inhibition of force was associated with reductions in both oxygen consumption and lactate production. No effects of felodipine could be observed in a calcium-free solution. The metabolic rates and force during felodipine inhibition approached those recorded in the calcium-free media. Felodipine (30 nM) did not alter the tissue levels of ATP, ADP, AMP and phosphocreatine. Relaxation by felodipine is thus associated with a decreased energy demand for contraction and, possibly, ionic translocation. The reduced ATP hydrolysis is compensated for by the regeneration of metabolic ATP, thus keeping the cellular levels of high-energy phosphates constant.
authors.affiliation: Department of Physiology and Biophysics, University of Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Arner
authors.forename: S L
authors.initials: SL
authors.lastname: Boström
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects*; D015736:Felodipine; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009568:Nitrendipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D010725:Phosphocreatine / Q000378:metabolism; D011169:Portal Vein / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000227:Adenine Nucleotides; D010725:Phosphocreatine; D009568:Nitrendipine; D015736:Felodipine