Tanaka K, Inoue S, Saito S, Nagase H, Takamura Y
Third Department of Internal Medicine, Yokohama City University School of Medicine, Japan.
J Auton Nerv Syst. 1993 Mar;42(3):225-31. doi: 10.1016/0165-1838(93)90367-4.
To clarify the physiological role of vagal amino acid sensors in the liver, the effect of hepatic vagotomy and/or celiac vagotomy (sectioning of the hepatic branch and/or the celiac branches of the vagus nerve) on the secretion of insulin and glucagon after intraperitoneal injection of neutral (L-alanine, L-leucine, and L-phenylalanine), acidic (L-glutamate), or nonmetabolized (cycloleucine) acids, was examined in rats. Hepatic vagotomy enhanced both plasma glucose and glucagon concentrations after intraperitoneal injection of alanine more than those in sham-vagotomized (control) rats, while after intraperitoneal injection of leucine, hepatic vagotomy decreased plasma glucose concentrations and enhanced plasma insulin concentrations more than in control animals. These effects, following both alanine and leucine administration, were blocked by celiac vagotomy. Glutamate, phenylalanine, and cycloleucine stimulation in hepatic-vagotomized rats caused no significant differences in plasma glucose, insulin, or glucagon levels as compared to those in sham-vagotomized rats. Celiac vagotomy alone did not affect plasma glucose, insulin, or glucagon concentrations after stimulation by these five amino acids. The physiological role of alanine and leucine sensors may be to prevent amino acid-induced exaggerated pancreatic hormone secretion and to maintain blood glucose homeostasis, while glutamate, phenylalanine, and cycloleucine have no effect on this pancreatic neuroendocrine system.
为阐明肝脏中迷走神经氨基酸传感器的生理作用，研究了肝迷走神经切断术和/或腹腔迷走神经切断术（切断迷走神经的肝支和/或腹腔支）对大鼠腹腔注射中性氨基酸（L-丙氨酸、L-亮氨酸和L-苯丙氨酸）、酸性氨基酸（L-谷氨酸）或非代谢性氨基酸（环亮氨酸）后胰岛素和胰高血糖素分泌的影响。腹腔注射丙氨酸后，肝迷走神经切断术组大鼠的血糖和胰高血糖素浓度升高幅度均大于假手术（对照）组大鼠；而腹腔注射亮氨酸后，肝迷走神经切断术组大鼠的血糖浓度降低，胰岛素浓度升高幅度均大于对照组动物。腹腔迷走神经切断术可阻断丙氨酸和亮氨酸给药后的这些效应。与假手术组大鼠相比，肝迷走神经切断术组大鼠经谷氨酸、苯丙氨酸和环亮氨酸刺激后，血糖、胰岛素或胰高血糖素水平无显著差异。单独进行腹腔迷走神经切断术不影响这五种氨基酸刺激后大鼠的血糖、胰岛素或胰高血糖素浓度。丙氨酸和亮氨酸传感器的生理作用可能是防止氨基酸诱导的胰腺激素过度分泌并维持血糖稳态，而谷氨酸、苯丙氨酸和环亮氨酸对该胰腺神经内分泌系统无影响。
