Okamoto S, Ibaraki K, Hayashi S, Saito M
Department of Biomedical Sciences, School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Brain Res. 1996 Nov 11;739(1-2):308-13. doi: 10.1016/s0006-8993(96)00840-2.
The ventromedial hypothalamic nucleus (VMH) has been proposed to be a locus intimately associated with sympathetic facilitation in peripheral tissues. To investigate a possible role of the VMH in controlling peripheral immune functions, we examined the effects of VMH stimulation on proliferative activity of lymphocytes isolated from the spleen in rats. Electrical stimulation of the VMH (2 s at every 30 s for 30 min) caused a remarkable decrease in the mitogenic response of splenic lymphocytes to Concanavalin A, whereas the stimulation of other hypothalamic regions such as the paraventricular nucleus did not show any significant effects. The suppressive effect of VMH stimulation was not influenced after adrenalectomy, suggesting a minor role of the adrenocortical system. In contrast, pretreatments with a ganglionic blocking agent (chlorisondamine) and a beta-adrenergic receptor antagonist (propranolol) completely reversed the suppressive effect. Surgical severing of the sympathetic nerves entering the spleen also reversed the effect of VMH stimulation. Together with the previous finding that VMH stimulation activates the splenic sympathetic nerves, it is concluded that the VMH suppresses the proliferative activity of splenic lymphocytes through the activation of sympathetic nerves via the beta-adrenergic pathway.
腹内侧下丘脑核（VMH）被认为是与外周组织交感神经促进密切相关的一个位点。为了研究VMH在控制外周免疫功能中的可能作用，我们检测了VMH刺激对从大鼠脾脏分离的淋巴细胞增殖活性的影响。VMH电刺激（每30秒刺激2秒，共30分钟）导致脾淋巴细胞对刀豆蛋白A的促有丝分裂反应显著降低，而刺激其他下丘脑区域如室旁核则未显示出任何显著影响。肾上腺切除术后，VMH刺激的抑制作用不受影响，提示肾上腺皮质系统作用较小。相反，用神经节阻断剂（氯异吲哚铵）和β-肾上腺素能受体拮抗剂（普萘洛尔）预处理可完全逆转抑制作用。切断进入脾脏的交感神经也可逆转VMH刺激的作用。结合之前VMH刺激可激活脾交感神经的发现，得出结论：VMH通过β-肾上腺素能途径激活交感神经来抑制脾淋巴细胞的增殖活性。
