Fowler C J, Vedin V, Sjöberg E
Department of Pharmacology and Clinical Neuroscience, Umeâ University, Umeâ, SE-901 87, Sweden.
Biochem Biophys Res Commun. 1999 Apr 13;257(2):629-34. doi: 10.1006/bbrc.1999.0522.
In the present study, the effects of the thiol oxidising agent diamide upon the properties of rat brain beta1-adrenergic and human platelet serotonin2A receptor recognition sites have been investigated using 3HCGP-12177 (in the presence of ICI-118551) and [3H]LSD as ligands. (-)Isoprenaline inhibited 3HCGP-12177 binding with nH values of 0.87, 0.67, and 0.56 for added Mg2+ concentrations of 0, 2.5, and 25 mM, respectively. Pretreatment with diamide increased the nH to above unity for the inhibition of the binding by (-)isoprenaline, without a concomitant effect on the inhibition of the binding by (-)propranolol. In contrast, diamide reduced the affinity of human platelet serotonin2A-receptors for antagonists, but did not consistently induce nH values above unity for the inhibition of antagonist binding by serotonin. These results suggest that cooperative interactions reported for cardiac muscarinic receptors may also occur for beta1-adrenergic receptors in the rat brain.
在本研究中，已使用3HCGP - 12177（在ICI - 118551存在下）和[3H]LSD作为配体，研究了硫醇氧化剂二酰胺对大鼠脑β1 - 肾上腺素能受体和人血小板5 - 羟色胺2A受体识别位点特性的影响。（-）异丙肾上腺素抑制3HCGP - 12177结合，对于添加的Mg2 +浓度分别为0、2.5和25 mM时，nH值分别为0.87、0.67和0.56。用二酰胺预处理可使（-）异丙肾上腺素抑制结合的nH增加至大于1，而对（-）普萘洛尔抑制结合没有伴随影响。相反，二酰胺降低了人血小板5 - 羟色胺2A受体对拮抗剂的亲和力，但对于5 - 羟色胺抑制拮抗剂结合，并未始终诱导nH值大于1。这些结果表明，报道的心脏毒蕈碱受体的协同相互作用也可能发生在大鼠脑的β1 - 肾上腺素能受体中。
