Ribes G, Hillaire-Buys D, Gross R, Blayac J P, Loubatières-Mariani M M
Faculté de Médecine, Laboratoire de Pharmacologie, UA 599 du CNRS, Institut de Biologie, Montpellier, France.
Eur J Pharmacol. 1989 Mar 21;162(2):207-14. doi: 10.1016/0014-2999(89)90283-5.
Yohimbine hydrochloride, an alpha 2-adrenoceptor antagonist, was administered (3.3 mg/kg i.v.) to anesthetized normal dogs provided with a T-shaped catheter inserted in the pancreaticoduodenal vein. The effects on blood glucose levels and pancreatic hormones were investigated. We show that yohimbine induced an immediate and pronounced stimulatory effect on insulin secretion accompanied by a clear decrease in blood glucose levels. Yohimbine also stimulated the pancreatic secretion of somatostatin and glucagon. However, the secretion kinetics were not the same for the three hormones: the stimulation was rapid and immediate for insulin and somatostatin, whereas it was progressive for glucagon. All these stimulatory effects were suppressed by propranolol, thus implicating beta-adrenergic mechanisms. Bilateral cervical vagotomy markedly reduced the immediate effect of yohimbine on insulin secretion, suggesting that a central neural pathway was implicated. In contrast, the progressive elevation in glucagon secretion was not decreased by vagotomy. Our results suggest that yohimbine stimulates, at least in part, insulin secretion by blocking central alpha 2-adrenoceptors.
盐酸育亨宾是一种α2肾上腺素能受体拮抗剂，以3.3毫克/千克的静脉注射剂量给予麻醉的正常犬，这些犬在胰十二指肠静脉中插入了T形导管。研究了其对血糖水平和胰腺激素的影响。我们发现，育亨宾对胰岛素分泌立即产生显著的刺激作用，同时血糖水平明显降低。育亨宾还刺激了生长抑素和胰高血糖素的胰腺分泌。然而，这三种激素的分泌动力学并不相同：胰岛素和生长抑素的刺激迅速且立即出现，而胰高血糖素的刺激则是渐进性的。所有这些刺激作用都被普萘洛尔抑制，因此涉及β肾上腺素能机制。双侧颈迷走神经切断术显著降低了育亨宾对胰岛素分泌的即时作用，表明涉及中枢神经通路。相比之下，迷走神经切断术并未降低胰高血糖素分泌的渐进性升高。我们的结果表明，育亨宾至少部分通过阻断中枢α2肾上腺素能受体来刺激胰岛素分泌。
