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Differential inhibition of secretagogue-stimulated sodium uptake in adrenal chromaffin cells by activation of D4 and D5 dopamine receptors.
- Source :
-
Journal of neurochemistry [J Neurochem] 1996 Nov; Vol. 67 (5), pp. 1960-4. - Publication Year :
- 1996
-
Abstract
- Recent studies have demonstrated that D1-selective and D2-selective dopamine receptor agonists inhibit catecholamine secretion and Ca2+ uptake into bovine adrenal chromaffin cells by receptor subtypes that we have identified by PCR as D5, a member of the D1-like dopamine receptor subfamily, and D4, a member of the D2-like dopamine receptor subfamily. The purpose of this study was to determine whether activation of D5 or D4 receptors inhibits influx of Na+, which could explain inhibition of secretion and Ca2+ uptake by dopamine agonists. D1-selective agonists preferentially inhibited both dimethylphenylpiperazinium- (DMPP) and veratridine-stimulated 22Na+ influx into chromaffin cells. The D1-selective agonists chloro-APB hydrobromide (CI-APB; 100 microM) and SKF-38393 (< 00 microM) inhibited DMPP-stimulated Na+ uptake by 87.5 +/- 2.3 and 59.7 +/- 4.5%, respectively, whereas the D2-selective agonist bromocriptine (100 microM) inhibited Na+ uptake by only 22.9 +/- 5.0%. Veratridine-stimulated Na+ uptake was inhibited 95.1 +/- 3.2 and 25.7 +/- 4.7% by 100 microM CI-APB or bromocriptine, respectively. The effect of CI-APB was concentration dependent. A similar IC50 (approximately 18 microM) for inhibition of both DMPP- and veratridine-stimulated Na+ uptake was obtained. The addition of 8-bromo-cyclic AMP (1 mM) had no effect on either DMPP- or veratridine-stimulated Na+ uptake. These observations suggest that D1-selective agonists are inhibiting secretagogue-stimulated Na+ uptake in a cyclic AMP-independent manner.
- Subjects :
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine pharmacology
Adrenal Medulla drug effects
Adrenal Medulla metabolism
Analysis of Variance
Animals
Benzazepines pharmacology
Biological Transport drug effects
Bromocriptine pharmacology
Cattle
Cells, Cultured
Chromaffin Cells drug effects
Colforsin pharmacology
Dimethylphenylpiperazinium Iodide pharmacology
Kinetics
Receptors, Dopamine D1 drug effects
Receptors, Dopamine D2 drug effects
Receptors, Dopamine D4
Receptors, Dopamine D5
Tetrodotoxin pharmacology
Veratridine pharmacology
Chromaffin Cells metabolism
Receptors, Dopamine D1 physiology
Receptors, Dopamine D2 physiology
Sodium metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3042
- Volume :
- 67
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Journal of neurochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 8863501
- Full Text :
- https://doi.org/10.1046/j.1471-4159.1996.67051960.x