Demonstration of a slowly dissociating form of bovine hippocampal synaptic membrane opiate receptors.
Demonstration of a slowly dissociating form of bovine hippocampal synaptic membrane opiate receptors.
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DOI：
10.1016/0014-2999(82)90284-9
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发表时间：
1982-09
影响因子：
5
通讯作者：
K. Pryhuber;B. Roth;C. Coscia
中科院分区：
文献类型：
--
作者：
K. Pryhuber;B. Roth;C. Coscia
We studied the binding characteristics of opiate receptors in synaptic plasma membranes isolated from bovine hippocampus. On the basis of kinetic binding studies the interaction of [3 H][D-Ala 2, D-Leu 5] enkephalin (DADL) with its receptor was an extremely slow process. Rates of association and dissociation were determined and a pseudo-first order rate constant for association calculated to be 5.68× 10 5 1/mol· s at 25° C. The rate of dissociation (t 1 2= 70 min) was accelerated by GTP and changed from linear to biphasic. The kinetically derived equilibrium dissociation constant (0.29 nM) was considerably lower than the K D obtained from Scatchard and Hill plots (1.24 nM). Measurement of DADL association as a function of temperature yielded a linear Arrhenius plot. Finally, competition binding assays revealed that δ-specific agonists exhibited relatively high potency in displacing [3 H] DADL from synaptic plasma membranes receptors whereas μ-specific agonists and antagonists were less effective. These results with bovine hippocampus may be explained by the formation of a slow-dissociating, high-affinity agonist conformation of the δ-opiate receptor which has been predicted for the system by the cyclic-allosteric and ternary complex models.
