Gurguis G N, Turkka J, Linnoila M
Psychiatry Service (116A), Department of Veterans' Affairs Medical Center, Dallas, TX 75216, USA.
Eur Neuropsychopharmacol. 1998 May;8(2):131-40. doi: 10.1016/s0924-977x(97)00059-x.
Most ligands which have been employed to investigate the regulation of beta-adrenergic receptors (betaAR) under pathophysiological conditions and in response to pharmacological manipulations have also been shown to have affinity for 5-HT1B receptors. We examined the effects of serotonin and metergoline (10 microM) on 125I-iodocyanopindolol (ICYP, 5-100 pM) binding to betaAR in rat frontal cortex and hippocampus membranes. In both brain regions, the presence of either serotonin or metergoline significantly lowered iodocyanopindolol dissociation constant (Kd) and maximum binding capacity (Bmax). Isoproterenol displacement curves showed that the decrease in receptor density was primarily due to a significant decrease in the receptors in the low-conformational state. Thus, a significant fraction of the apparent ICYP binding to betaAR in the low-conformational state was due to binding to 5-HT1B receptors. Neither serotonin nor metergoline had an effect on the agonist isoproterenol dissociation constant from betaAR in either conformational state.
大多数用于研究病理生理条件下以及对药理学操作产生反应时β-肾上腺素能受体（βAR）调节作用的配体，也已被证明对5-HT1B受体具有亲和力。我们研究了血清素和麦角苄酯（10微摩尔）对大鼠额叶皮质和海马膜中125I-碘氰吲哚洛尔（ICYP，5-100皮摩尔）与βAR结合的影响。在这两个脑区，血清素或麦角苄酯的存在均显著降低了碘氰吲哚洛尔的解离常数（Kd）和最大结合容量（Bmax）。异丙肾上腺素置换曲线表明，受体密度的降低主要是由于低构象状态下受体的显著减少。因此，低构象状态下与βAR明显结合的ICYP的很大一部分是由于与5-HT1B受体结合所致。血清素和麦角苄酯对处于任一构象状态的βAR的激动剂异丙肾上腺素解离常数均无影响。
