Sved A F, Tsukamoto K, Schreihofer A M
Department of Behavioral Neuroscience, University of Pittsburgh, PA 15260.
Brain Res. 1992 Apr 3;576(2):297-303. doi: 10.1016/0006-8993(92)90693-4.
Bilateral injection into the nucleus tractus solitarius (NTS) of the alpha 2-adrenergic receptor antagonist yohimbine produced a dose-related (10-500 pmol) increase in arterial pressure, with a maximal response of approximately 60 mm Hg. Idazoxan, also an alpha 2-adrenergic receptor antagonist, produced a similar response although idazoxan was less potent than yohimbine. The pressor response elicited by these drugs was attenuated by stimulation of adrenergic receptors in the NTS by local administration of either clonidine or tyramine. Doses of yohimbine (200 pmol) or idazoxan (5 nmol) that maximally increased arterial pressure also completely inhibited the depressor and bradycardic responses to electrical stimulation of the aortic depressor nerve. These results indicate that tonic stimulation of alpha 2-adrenergic receptors in the NTS is required for baroreceptor reflex function.
将α2 - 肾上腺素能受体拮抗剂育亨宾双侧注入孤束核（NTS）会使动脉血压呈剂量相关（10 - 500皮摩尔）升高，最大反应约为60毫米汞柱。咪唑克生也是一种α2 - 肾上腺素能受体拮抗剂，尽管其效力低于育亨宾，但也产生了类似的反应。通过在NTS局部给予可乐定或酪胺刺激肾上腺素能受体，可减弱这些药物引发的升压反应。使动脉血压最大程度升高的育亨宾剂量（200皮摩尔）或咪唑克生剂量（5纳摩尔）也完全抑制了对主动脉减压神经电刺激的降压和心动过缓反应。这些结果表明，NTS中α2 - 肾上腺素能受体的紧张性刺激是压力感受器反射功能所必需的。
