Kessler J P, Jean A
Brain Res. 1986 Oct 29;386(1-2):69-77. doi: 10.1016/0006-8993(86)90142-3.
The present study was carried out to elucidate the influence of catecholamines on swallowing, a polysynaptic reflex organized by an interneuronal network localized mainly within the lateral solitary complex (LSC) of the medulla oblongata. The effects of catecholaminergic agents were investigated in the rat, on rhythmic swallowing elicited by repetitive stimulation of the superior laryngeal nerve (SLN). Catecholaminergic agents were microinjected by pressure application, through multibarrelled glass micropipettes, into the LSC including the tractus solitarius, the swallowing region of the nucleus of the solitary tract and the adjacent reticular formation. Microinjections of noradrenaline (NA, 0.1-5 nmol, 50 nl) induced a significant decrease of the number and the amplitude of the rhythmic swallows elicited by stimulation of the ipsilateral SLN. This inhibitory effect was dose-related. Microinjections of clonidine (2.5 nmol, 50 nl), dopamine (0.25-2.5 nmol, 50 nl) and apomorphine (0.5 nmol, 50 nl), also inhibited swallowing. No significant modification of swallowing was induced by control injections of the vehicle (50 nl) within the active sites. Moreover the NA-induced inhibition of swallowing, was significantly antagonized by pretreatment with the alpha-adrenergic blocker phentolamine applied locally in the LSC. Furthermore neither blood pressure, nor respiratory rhythm were consistently modified by the catecholaminergic microinjections, indicating that the catecholamine-induced inhibition of swallowing was not a secondary side effect originating from alteration of these functions. It can therefore be concluded that the present results demonstrate the existence within the LSC of a catecholaminergic inhibition of the swallowing reflex. This inhibitory effect likely arises from activation of specific catecholaminergic receptors and affects the swallowing structures localized within the LSC, i.e., the laryngeal swallowing afferents running in the solitary tract and/or the swallowing interneurons within the nucleus of the solitary tract.
本研究旨在阐明儿茶酚胺对吞咽的影响，吞咽是一种多突触反射，由主要位于延髓外侧孤束复合体（LSC）内的中间神经元网络组织。在大鼠中研究了儿茶酚胺能药物对喉上神经（SLN）重复刺激诱发的节律性吞咽的影响。通过压力应用，将儿茶酚胺能药物通过多管玻璃微量移液器微量注射到包括孤束、孤束核吞咽区和相邻网状结构的LSC中。去甲肾上腺素（NA，0.1 - 5 nmol，50 nl）的微量注射导致同侧SLN刺激诱发的节律性吞咽的次数和幅度显著减少。这种抑制作用与剂量相关。可乐定（2.5 nmol，50 nl）、多巴胺（0.25 - 2.5 nmol，50 nl）和阿扑吗啡（0.5 nmol，50 nl）的微量注射也抑制吞咽。在活性部位注射对照载体（50 nl）未引起吞咽的显著改变。此外，NA诱导的吞咽抑制可被在LSC局部应用的α - 肾上腺素能阻滞剂酚妥拉明预处理显著拮抗。此外，儿茶酚胺能微量注射并未持续改变血压和呼吸节律，表明儿茶酚胺诱导的吞咽抑制不是这些功能改变引起的继发性副作用。因此可以得出结论，本研究结果证明了LSC内存在对吞咽反射的儿茶酚胺能抑制作用。这种抑制作用可能源于特定儿茶酚胺能受体的激活，并影响LSC内的吞咽结构，即孤束中运行的喉吞咽传入神经和/或孤束核内的吞咽中间神经元。
