Hall M E, Miley F B, Stewart J M
University of Colorado School of Medicine, Denver 80262.
Brain Res. 1989 Sep 18;497(2):280-90. doi: 10.1016/0006-8993(89)90273-4.
Microinjection of the neuropeptide substance P (SP) into the baroreceptor portions of the nucleus of the solitary tract (NTS) caused a dose-dependent decrease in blood pressure (BP) and heart rate (HR), consistent with the putative role for SP as a transmitter in the baroreceptor reflex arc. In contrast, SP elevated BP and HR when microinjected into the adjacent area postrema. Structure-activity studies of effects of SP in the NTS revealed that an aminoterminal heptapeptide fragment of SP could fully reproduce the depressor and bradycardic effects of SP. In contrast, a carboxyterminal hexapeptide fragment of SP significantly elevated both BP and HR. The structural requirements for aminoterminal fragment effects were quite specific in terms of peptide length and sensitivity to D-amino acid substitutions. These findings are consistent with a role for SP as a baroreceptor reflex transmitter and suggest, furthermore, that this action is mediated by the aminoterminal region of SP.
将神经肽P物质（SP）微量注射到孤束核（NTS）的压力感受器部分会导致血压（BP）和心率（HR）呈剂量依赖性下降，这与SP作为压力感受器反射弧中的一种递质的假定作用相一致。相比之下，当将SP微量注射到邻近的最后区时，会使血压和心率升高。对SP在NTS中的作用进行的构效关系研究表明，SP的氨基末端七肽片段能够完全重现SP的降压和减慢心率作用。相反，SP的羧基末端六肽片段会显著升高血压和心率。氨基末端片段作用的结构要求在肽长度和对D-氨基酸取代的敏感性方面相当特殊。这些发现与SP作为压力感受器反射递质的作用一致，此外还表明这种作用是由SP的氨基末端区域介导的。
