Washburn B S, Jiang J C, Cummings S L, Dixon K, Gietzen D W
Department of Medicine, School of Veterinary Medicine, University of California, Davis 95616.
Am J Physiol. 1994 Jun;266(6 Pt 2):R1922-7. doi: 10.1152/ajpregu.1994.266.6.R1922.
We investigated the roles of the vagus nerve and the serotonin3 (5-HT3) receptor in mediating the food intake depression associated with amino acid deficiency. The food intake of sham-operated (sham) rats given an isoleucine-imbalanced (IMB) diet was reduced to < 40% of control basal (BAS) diet intake (P = 0.0009), and pretreatment with the 5-HT3 antagonist tropisetron (Trop) increased IMB intake by twofold over the vehicle (VEH)-treated group (P < or = 0.0001), as we have reported before. However, after subdiaphragmatic vagotomy (VAGX), IMB intake was increased to a level intermediate between the sham-VEH and sham-Trop groups, while administration of Trop did not increase IMB intake over VAGX alone. By the end of day 1, the VAGX-Trop group had eaten only 1 g more of IMB than the VAGX-VEH group (NS). We conclude that 1) the vagus is among the physiological systems involved in the anorectic responses to IMB and 2) intact vagal function is necessary for the full effect of 5-HT3 antagonists in alleviating the anorectic responses to IMB.
我们研究了迷走神经和5-羟色胺3（5-HT3）受体在介导与氨基酸缺乏相关的食物摄入减少中的作用。如我们之前所报道，给予异亮氨酸失衡（IMB）饮食的假手术（sham）大鼠的食物摄入量减少至对照基础（BAS）饮食摄入量的<40%（P = 0.0009），并且用5-HT3拮抗剂托烷司琼（Trop）预处理使IMB摄入量比载体（VEH）处理组增加了两倍（P≤0.0001）。然而，在膈下迷走神经切断术（VAGX）后，IMB摄入量增加到假手术-VEH组和假手术-Trop组之间的中间水平，而给予Trop并没有使IMB摄入量比单独VAGX组增加。到第1天结束时，VAGX-Trop组比VAGX-VEH组仅多吃了1克IMB（无显著性差异）。我们得出结论：1）迷走神经是参与对IMB厌食反应的生理系统之一；2）完整的迷走神经功能对于5-HT3拮抗剂在减轻对IMB厌食反应中的充分作用是必要的。
