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| In this paper, the possible regulation of selective beta 1- and beta 2-adrenoreceptor agonists or antagonists on galanin (Gal) expression in organotypically cultured superior cervical ganglion (SCG) neurons was evaluated. Gal, a 29-amino-acid neuropeptide in most species (30-amino-acid in human), is expressed in SCG neurons and plays a trophic role in the adult animal and acts as an inhibitory modulator of cholinergic and noradrenergic neurotransmission. Whether beta-adrenoreceptors are involved in modulation on Gal expression in SCG neurons remains unknown. In the present study, after acute (4 hours) or chronic (4 days) incubation with these agonists or antagonists, the expression of Gal and its mRNA were estimated by double fluorescent labeling and real time-PCR, respectively. The results showed that the amount of Gal and Gal mRNA expression in organotypically cultured SCG neurons decreased significantly after chronic stimulation with beta 2-adrenoreceptor agonist salbutamol as compared with that in control group. Beta 1-adrenoreceptor agonist denopamine, antagonist metoprolol, and beta 2-adrenoreceptor antagonist ICI118551 chronic stimulation did not have effects on Gal and Gal mRNA expression. The expression of Gal and its mRNA did not significantly change after acute exposure of these agents. These data implicated that Gal may be regulated by chronic activation beta 2-adrenoreceptors, but not beta 1-adrenoreceptors in sympathetic neurons. |
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| Keywords:neurobiology; adrenoreceptor; galanin; superior cervical ganglion; sympathetic neuron |
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