Species-independent metabolic response to an increase of [Ca(2+)](i) in quiescent cardiac muscle
| Autor: | Denis S. Loiselle, Peter J Hanley, Patricia J Cooper, Marie-Louise Ward |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
medicine.medical_specialty
Physiology Guinea Pigs Energy metabolism chemistry.chemical_element Biology In Vitro Techniques Oxygen Intracellular ca Oxygen Consumption Species Specificity Physiology (medical) Internal medicine medicine Extracellular Animals Calcium Signaling Rats Wistar Fluorescent Dyes Pharmacology Endoplasmic reticulum Myocardium Sodium Cardiac muscle Heart Rats Kinetics medicine.anatomical_structure Endocrinology Energy expenditure chemistry Biophysics Metabolic rate Calcium Fura-2 |
| Zdroj: | Clinical and experimental pharmacologyphysiology. 30(8) |
| ISSN: | 0305-1870 |
| Popis: | 1. The aim of the present investigation was to contrast the Ca 2 + dependence of cardiac energy metabolism in two species with differential reliance on extracellular Ca 2 + for excitation-contraction coupling. 2. We measured energy expenditure as the rate of oxygen consumption (vo 2 ) of isolated, Langendorff-perfused hearts of rats and guinea-pigs during KCl arrest. In parallel experiments, we indexed intracellular Ca 2 + concentration ([Ca 2 + ] i ) of isolated right-ventricular trabeculae, using the Ca 2 + fluorophore fura-2 and ratiometric spectrofluorometry. By varying extracellular Na + concentration ([Na + ] 0 ), Vo 2 -[Na + ] 0 and [Ca 2 + ] i -[Na + ] 0 relationships were constructed for each species. 3. Reduction of [Na + ] 0 during K + arrest caused pronounced species-dependent elevations of both Vo 2 and [Ca 2 + ] i . Despite the species dependence of both Vo 2 and [Ca 2 + ] i on [Na + ] 0 , a single species-independent Vo 2 -[Ca 2 + ] i relationship obtained. 4. We infer that elevation of the metabolic rate of the arrested heart above its basal value is determined primarily by [Ca 2 + ] i and is not species dependent. |
| Databáze: | OpenAIRE |
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