Nonogaki K, Iguchi A, Sakamoto N
Third Department of Internal Medicine, Nagoya University School of Medicine, Aichi, Japan.
J Neuroendocrinol. 1994 Aug;6(4):443-6. doi: 10.1111/j.1365-2826.1994.tb00605.x.
The influence of bicuculline methiodide (BMI), a gamma-aminobutyric acid (GABA) receptor antagonist, on central nervous system regulation of blood glucose homeostasis was studied in fed rats. Injection of BMI (1-10 nmol) into the third ventricle was found to produce hepatic venous hyperglycemia in a dose-dependent manner. This change was associated with increased secretion of epinephrine and glucagon. The role of epinephrine in hyperglycemia was then studied in bilaterally adrenalectomized (ADX) rats injected with BMI. Plasma glucose concentration was found to increase in ADX rats although the level was approximately half that for intact rats and significantly higher than for controls. The increase in epinephrine and glucagon secretion seen in intact rats, but not in ADX rats, suggests BMI induced epinephrine release is responsible for the glucagon secretion. Three possible mechanisms are suggested to account for the rise in plasma glucose in the hepatic vein after injection of BMI: 1) that epinephrine is secreted by the adrenal medulla, 2) that epinephrine secretion stimulates glucagon secretion or 3) that there may be some direct innervation of the liver in rats.
在饱食的大鼠中研究了γ-氨基丁酸（GABA）受体拮抗剂荷包牡丹碱甲碘化物（BMI）对中枢神经系统调节血糖稳态的影响。向第三脑室内注射BMI（1 - 10纳摩尔）会以剂量依赖的方式导致肝静脉血糖升高。这种变化与肾上腺素和胰高血糖素分泌增加有关。随后在注射了BMI的双侧肾上腺切除（ADX）大鼠中研究了肾上腺素在高血糖中的作用。发现ADX大鼠的血浆葡萄糖浓度升高，尽管该水平约为完整大鼠的一半，但明显高于对照组。完整大鼠中出现的肾上腺素和胰高血糖素分泌增加，而ADX大鼠中未出现，这表明BMI诱导的肾上腺素释放是胰高血糖素分泌的原因。提出了三种可能的机制来解释注射BMI后肝静脉血浆葡萄糖升高的原因：1）肾上腺素由肾上腺髓质分泌，2）肾上腺素分泌刺激胰高血糖素分泌，或3）大鼠肝脏可能存在一些直接神经支配。
