Catecholamine secretory response to calcium reintroduction in the perfused cat adrenal gland treated with ouabain
| Autor: | Enrique Esquerro, Antonio G. García, J. C. Prat, Magdalena Herandez, Sadashiv M. Kirpekar |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
medicine.medical_specialty
Sodium chemistry.chemical_element In Vitro Techniques Calcium Biochemistry Ouabain Catecholamines Internal medicine Adrenal Glands medicine Animals Secretion Pharmacology Chemistry Depolarization Kinetics Endocrinology medicine.anatomical_structure Chromaffin cell Cats Potassium Catecholamine Intracellular medicine.drug |
| Zdroj: | Biochemical Pharmacology. 29:2669-2673 |
| ISSN: | 0006-2952 |
| DOI: | 10.1016/0006-2952(80)90084-2 |
| Popis: | The effect of external [Na] o , internal sodium [Na] i and external calcium [Ca] o concentrations on the secretion of catecholamines (CA) from the retrogradely perfused and ouabain-treated cat adrenal gland was investigated. CA release in response to a pulse of ouabain was [Ca] o dependent. Inhibition of the sodium pump with the glycoside allowed the loading of the chromaffin cells with different Na concentrations in the absence of [Ca] o . [Ca] o reintroduction evoked a CA secretory response which was directly proportional to the loading Na concentration and therefore to the internal concentration of this ion [Na] i The secretory response evoked by [Ca] o in a Na-loaded gland was inversely related to [Na] o at the moment of [Ca] o reintroduction, secretion being higher at lower [Na] o . Half-time (t 1 2 ) for the decline from the peak secretory response after [Ca] o introduction was related to the [Na] o at the time of [Ca] o introduction. However, the rate of decay of CA secretion was independent of [Na] i at the time of [Ca] o application. Addition of [Ca] o , to a ouabain-treated gland during perfusion with 140 mM K- and CA-free solution resulted in a secretory response which was much greater than that obtained in untreated glands. The data imply that ouabain-induced secretion was not mediated only by cell depolarization. It is concluded that the secretory response to [Ca] o in a ouabain-treated gland is the consequence of a rise of intracellular ionized Ca levels, presumably resulting from the activation of an internal Na-dependent Ca influx system located in the chromaffin cell membrane. |
| Databáze: | OpenAIRE |
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