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：1974
卷号：71
期号：1
页码：128-131
DOI：10.1073/pnas.71.1.128
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Calcium acting through the ionophore A-23187 caused massive K+ release from rat parotid slices. The ionophore thus simulates the action of epinephrine on the [α]-adrenergic receptor in this system. The [α]-adrenergic and cholinergic receptors are, however, not involved in the action of the ionophore since phetolamine and atropine had no effect on the ionophore-induced K+ release. Amylase secretion, which is induced by epinephrine through the {beta}-adrenergic receptor but does not require Ca++ in the medium, was only slightly increased by the ionophore in the presence of Ca++. The K+ released by Ca++ through the ionophore was regained by the cells upon chelation of Ca++ with ethylene glycol bis({beta}-aminoethyl ether)-N,N'-tetraacetic acid. Similar to the action of epinephrine on the [α]-adrenergic receptor, the K+ release induced by the ionophore is specific for Ca++, which cannot be substituted by 2.5 mM Sr++, Mg++, or Ba++. The results suggest that epinephrine, like the ionophore, introduces Ca++ into the cell to mediate K+ release. It is proposed that the ionophore A-23187 may be an effective probe to test whether other Ca++-requiring hormones and neurotransmitters act in a similar fashion to produce their diverse physiological responses.
