de Jong W, Nijkamp F P, Bohus B
Arch Int Pharmacodyn Ther. 1975 Feb;213(2):272-84.
Noradrenaline and alpha-methylnoradrenaline applied to the area of the nucleus tractus solitarii of the medulla oblongata decreased arterial blood pressure and heart rate of anesthetized normotensive rats. Alpha-Methylnoradrenaline was more effective than noradrenaline. Prior administration of the alpha-adrenergic blocking agent phentolamine at the same site prevented the central inhibitory action of the two catecholamines and even reversed the effect on blood pressure. The hypotensive responses evoked by electrical stimulation or alpha-methylnoradrenaline application were found to have a common distribution of the most effective site, comprising the middle-caudal part of the nucleus tractus solitarii at the obex level. Bilateral electrolytic lesions of this area caused an immediate and severe hypertension. The data suggest that the area of the nucleus tractus solitarii is a site of action of hypotensive drugs which may act by noradrenergic receptor stimulation in the brain. In addition brain serotonin may also play an inhibitory role as indicated by the association of elevated blood pressure and brainstem serotonin depletion during treatment with para-chorophenylalanine of normotensive and genetic hypertensive rats.
将去甲肾上腺素和α-甲基去甲肾上腺素应用于延髓孤束核区域，可降低麻醉的正常血压大鼠的动脉血压和心率。α-甲基去甲肾上腺素比去甲肾上腺素更有效。事先在同一部位给予α-肾上腺素能阻断剂酚妥拉明，可防止这两种儿茶酚胺的中枢抑制作用，甚至逆转对血压的影响。发现电刺激或应用α-甲基去甲肾上腺素引起的降压反应在最有效部位有共同的分布，包括闩部水平孤束核的中尾部。该区域的双侧电解损伤导致立即且严重的高血压。数据表明，孤束核区域是降压药物的作用部位，这些药物可能通过刺激脑内的去甲肾上腺素能受体发挥作用。此外，如在正常血压和遗传性高血压大鼠用对氯苯丙氨酸治疗期间，血压升高与脑干5-羟色胺耗竭相关所表明的，脑5-羟色胺也可能起抑制作用。
