Abstract
We have studied the functional interaction of dopamine with alpha1-adrenoceptor subtypes by measuring intracellular Ca2+ levels in pineal cells, a cell type where adrenoceptors are well characterized. We show that dopamine induces transient intracellular Ca2+ signals in only 70% of cells responding to phenylephrine. Dopamine-induced Ca2+ signals desensitise faster than Ca2+ transients elicited with phenylephrine and are selectively blocked by desipramine, imipramine, and alpha1B-adrenoceptor antagonists. These results suggest that dopamine induced Ca2+ signals are mainly due to the activation of one subtype of alpha-adrenoceptor, the alpha1B.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenergic alpha-1 Receptor Antagonists
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Adrenergic alpha-Antagonists / pharmacology
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Animals
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Calcium / metabolism*
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Dopamine / pharmacology*
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Dopamine Agonists / pharmacology
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Male
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Phenylephrine / pharmacology
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Pineal Gland / drug effects*
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Pineal Gland / metabolism
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Prazosin / pharmacology
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Rats
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Rats, Wistar
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Receptors, Adrenergic, alpha-1 / drug effects*
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Receptors, Catecholamine / antagonists & inhibitors
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Signal Transduction
Substances
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Adra1b protein, rat
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Adrenergic alpha-1 Receptor Antagonists
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Adrenergic alpha-Antagonists
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Dopamine Agonists
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Receptors, Adrenergic, alpha-1
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Receptors, Catecholamine
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Phenylephrine
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Calcium
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Dopamine
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Prazosin