Ladenheim E E, Jensen R T, Mantey S A, Moran T H
Johns Hopkins University School of Medicine, Department of Psychiatry and Behavioral Sciences, Baltimore, MD 21205.
Brain Res. 1992 Oct 16;593(2):168-78. doi: 10.1016/0006-8993(92)91305-x.
We have previously demonstrated the presence of two distinct bombesin receptor subtypes in the rat CNS and distinguished them as bombesin/gastrin-releasing peptide (BBS/GRP) and neuromedin B (NMB)-preferring binding sites. In the present study, we conducted a complete evaluation of the distribution of these binding sites throughout the rat brain using in vitro receptor autoradiography. The BBS/GRP-preferring binding sites were characterized as those that bound 125I-(Tyr4)BBS but not 125I-(D-Tyr0)NMB. At these sites 125I-(Tyr4)BBS binding was inhibited in the presence of 100 nM BBS but not by the same concentration of NMB. In contrast, NMB-preferring sites bound both radioligands and binding at these sites was inhibited in the presence of 100 nM NMB. Our results indicate that the distributions of BBS/GRP and NMB-preferring binding sites are widespread and distinct at all levels of the rat brain suggesting these peptides mediate separate functions in the rat central nervous system.
我们先前已证实在大鼠中枢神经系统中存在两种不同的蛙皮素受体亚型，并将它们区分为对蛙皮素/胃泌素释放肽（BBS/GRP）和神经介素B（NMB）具有优先亲和力的结合位点。在本研究中，我们使用体外受体放射自显影技术对这些结合位点在大鼠全脑的分布进行了全面评估。对BBS/GRP具有优先亲和力的结合位点被定义为那些能结合125I-(Tyr4)BBS但不能结合125I-(D-Tyr0)NMB的位点。在这些位点，125I-(Tyr4)BBS的结合在存在100 nM BBS时受到抑制，但相同浓度的NMB则无此作用。相反，对NMB具有优先亲和力的位点能结合两种放射性配体，且在存在100 nM NMB时这些位点的结合受到抑制。我们的结果表明，对BBS/GRP和NMB具有优先亲和力的结合位点分布广泛且在大鼠脑的各个水平上都有所不同，这表明这些肽在大鼠中枢神经系统中发挥着不同的功能。
