Chen C, Chen M Q, Wang H X, Chen Y
Proc Chin Acad Med Sci Peking Union Med Coll. 1989;4(3):142-6.
The central mechanism of the pressor response induced by stimulation of the central ends of abdominal vagi (SCAV) was studied in 33 anesthetized cats. The results of the experiments showed that both electro-stimulation to part of the nucleus tractus solitarius (NTS) and SCAV caused similar rises of blood pressure. The microinjection of kainic acid into the NTS (40 mmol/L, 2 microliters) evoked a prolonged rise of blood pressure but did not affect the pressor response induced by SCAV. Electro-stimulation of the locus coeruleus (LC) also elicited a pressor effect. Kainic acid at blocking dose (40 mmol/L, 2 microliters bilaterally injected into the LC induced an increase followed by a decrease in blood pressure and markedly attenuated the SCAV's pressor response. Bilateral microinjections of phentolamine (4 micrograms/2 microliters), propranolol (2 micrograms/2 microliters) or 6-hydroxydopamine (6-OHDA, 8 micrograms/2 microliters) into LC had no significant effect on the pressor response, but atropine could markedly attenuate it. These results suggest that the pressor afferents in abdominal vagi do not terminate in but pass through the NTS and the neurons in the LC play an important role in the SCAV pressor reflex. Cholinergic transmission rather than catecholaminergic transmission in the LC may be involved in this pressor response.
在33只麻醉猫中研究了刺激腹部迷走神经中枢端（SCAV）引起升压反应的中枢机制。实验结果表明，电刺激孤束核（NTS）的部分区域和SCAV均可引起相似的血压升高。向NTS微量注射海人酸（40 mmol/L，2微升）可引起血压长时间升高，但不影响SCAV引起的升压反应。电刺激蓝斑（LC）也可引起升压效应。阻断剂量的海人酸（40 mmol/L，双侧向LC注射2微升）可使血压先升高后降低，并显著减弱SCAV的升压反应。双侧向LC微量注射酚妥拉明（4微克/2微升）、普萘洛尔（2微克/2微升）或6-羟基多巴胺（6-OHDA，8微克/2微升）对升压反应无显著影响，但阿托品可显著减弱该反应。这些结果表明，腹部迷走神经的升压传入纤维并不终止于NTS，而是经过NTS，并且LC中的神经元在SCAV升压反射中起重要作用。LC中的胆碱能传递而非儿茶酚胺能传递可能参与了该升压反应。
