Muscarinic Receptor Binding in Sheep Anterior Pituitary
作者:
David R. Burt,
Richard L. Taylor,
期刊:
Neuroendocrinology
(Karger Available online 1980)
卷期:
Volume 30,
issue 6
页码: 344-349
ISSN:0028-3835
年代: 1980
DOI:10.1159/000123026
出版商: S. Karger AG
关键词: Pituitary gland;Muscarinic receptors;Acetylcholine;Releasing hormone;Quinuclidinyl benzilate
数据来源: Karger
摘要:
The existence of typical muscarinic receptors in membranes of sheep anterior pituitary was detected by binding of [3H]quinuclidinyl benzilate ([3H]QNB), a potent and specific muscarinic antagonist. [3H]QNB binding sites in anterior pituitary had an equilibrium dissociation constant of about 20–40 pM, a rate constant for association at 37 C of about 2 × 108M–1 min–1, a rate constant for dissociation at 37 C of about 4 × 10–3 min-1 and the expected specificities for a variety of choiinergic and other drugs. The concentration of [3H]QNB binding sites in anterior pituitary, about 4–6 pmol/g tissue, was at least twice that in posterior pituitary, but less than a quarter that in the hypothalamus. Since there is no established choiinergic or other innervation of the anterior pituitary, the presence there of typical muscarinic receptors, if we assume that they are functional, suggests that acetylcholine reaches the tissue through the hypophyseal portal circulation, and that it may thus have a role in the regulation of pituita
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