期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：2
页码：599-603
DOI：10.1073/pnas.80.2.599
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The role played by postsynaptic alpha-adrenergic receptors in the stimulation of pineal N-acetyltransferase (EC 2.3.1.5 ) and [3H]melatonin production was investigated in the rat. In vivo studies indicated that phenylephrine, an alpha-adrenergic agonist, potentiated and prolonged the effects of isoproterenol, a beta-adrenergic agonist. Similar observations were made in organ culture with glands devoid of functional nerve endings. In addition, a combination of 1 microM prazosin, an alpha 1-adrenergic blocking agent, and 1 microM propranolol, a beta-adrenergic blocking agent, was many times more potent then either agent alone in blocking the stimulatory effects of norepinephrine on N-acetyltransferase activity and [3H]melatonin production. These findings establish that norepinephrine acting through alpha- and beta-adrenergic receptors stimulates rat pineal N-acetyltransferase activity and, as a result, the production of melatonin. Apparently, beta-adrenergic activation is an absolute requirement, and an alpha-adrenergic receptor mechanism potentiates beta-adrenergic activation. These findings are significant because they demonstrate alpha-adrenergic potentiation of beta-adrenergic effects. In addition, they indicate that the widely held belief that melatonin production is regulated exclusively by a postsynaptic beta-adrenergic mechanism must be revised.
