Lopes P, Kar S, Tousignant C, Regoli D, Quirion R, Couture R
Department of Physiology, Faculty of Medicine, University of Montréal, Québec, Canada.
Synapse. 1993 Sep;15(1):48-57. doi: 10.1002/syn.890150106.
The present study aimed to localize and characterize [125I-Tyr8]-BK binding sites in all major segments of the guinea pig spinal cord using in vitro quantitative receptor autoradiography. [125I-Tyr8]-BK specific binding sites were localized predominantly in superficial layers of the dorsal horn, with lamina II depicting the highest labelling. The density of specific binding in laminae I and III was moderate, whereas in other areas, i.e., laminae IV-X, lower amounts of labelling were noticed. The B2 receptor antagonists D-Arg[Hyp3,Thi5,D-Tic7,Oic8]-BK (Hoe 140), D-Arg[Hyp3,D-Phe7,Leu8]-BK, Tyr0,D-Arg[Hyp3,D-Phe7,Leu8]-BK, D-Arg[Tyr3,D-Phe7,Leu8]-BK, D-Arg[Hyp2,Thi5,8,D-Phe7]-BK, D-Arg[Hyp3,Leu8]-BK and D-Arg[Hyp3,Gly6,Leu8]-BK as well as unlabelled [Tyr8]-BK inhibited [125I-Tyr8]-BK binding with respective Ki values of 0.04, 12.4, 23.4, 34.5, 43.5, 33.5, 23.0, and 0.6 nM while B1 related molecules (Tyr0,des-Arg10-kallidin and [Leu8]-des-Arg9-BK) did not significantly inhibit [125I-Tyr8]-BK binding up to micromolar concentrations. These results indicate that the specific [125I-Tyr8]-BK binding sites present in the guinea pig spinal cord belong to the B2 receptor subtype. The high density of B2 binding sites in the substantia gelatinosa provides an anatomical evidence in favour of a role for BK as a modulator of nociceptive information.
本研究旨在利用体外定量受体放射自显影技术，对豚鼠脊髓所有主要节段中的[125I-Tyr8]-BK结合位点进行定位和特性分析。[125I-Tyr8]-BK特异性结合位点主要定位于背角浅层，其中Ⅱ层的标记最强。Ⅰ层和Ⅲ层的特异性结合密度适中，而在其他区域，即Ⅳ-X层，标记量较低。B2受体拮抗剂D-Arg[Hyp3,Thi5,D-Tic7,Oic8]-BK（Hoe 140）、D-Arg[Hyp3,D-Phe7,Leu8]-BK、Tyr0,D-Arg[Hyp3,D-Phe7,Leu8]-BK、D-Arg[Tyr3,D-Phe7,Leu8]-BK、D-Arg[Hyp2,Thi5,8,D-Phe7]-BK、D-Arg[Hyp3,Leu8]-BK和D-Arg[Hyp3,Gly6,Leu8]-BK以及未标记的[Tyr8]-BK均可抑制[125I-Tyr8]-BK的结合，其各自的Ki值分别为0.04、12.4、23.4、34.5、43.5、33.5、23.0和0.6 nM，而与B1相关的分子（Tyr0,des-Arg10-缓激肽和[Leu8]-des-Arg9-BK）在微摩尔浓度范围内均未显著抑制[125I-Tyr8]-BK的结合。这些结果表明，豚鼠脊髓中存在的特异性[125I-Tyr8]-BK结合位点属于B2受体亚型。胶状质中B2结合位点的高密度为BK作为伤害性信息调节剂的作用提供了解剖学证据。
