Greenberg G R
Department of Medicine, University of Toronto, Canada.
Gastroenterology. 1987 Nov;93(5):994-1001. doi: 10.1016/0016-5085(87)90561-0.
Plasma gastrin and somatostatin responses to ingestion of a solid meal, to insulin hypoglycemia, and to intravenous infusion of gastrin-releasing peptide were measured in 4 conscious dogs with and without bilateral cryogenic blockade of the cervical vagus nerves. Vagal cooling to -2 degrees C abolished meal-stimulated rises in plasma gastrin and somatostatin. Atropine did not modify the gastrin response to cooling but bethanechol reduced the magnitude of inhibition to 37% +/- 9% without influencing plasma somatostatin. Gastrin-releasing peptide elevated postprandial plasma gastrin during vagal blockade to levels comparable to those with the vagus intact but did not alter the nadir plasma somatostatin response. The plasma gastrin and somatostatin rises associated with insulin hypoglycemia were similarly inhibited by cooling to -2 degrees C. Cooling to 12 degrees C, which selectively blocks vagal inhibitory pathways, had no effect on meal-stimulated gastrin release and partially decreased the plasma gastrin response to insulin hypoglycemia. Thus, gastrin release by food and by insulin hypoglycemia is mediated by a vagal nonmuscarinic excitatory pathway that is independent of changes in circulating plasma somatostatin but may include participation by the candidate neurotransmitter gastrin-releasing peptide.
在4只清醒犬中，分别在双侧颈迷走神经未阻断和阻断的情况下，测量了血浆胃泌素和生长抑素对固体餐摄入、胰岛素低血糖以及静脉输注胃泌素释放肽的反应。将迷走神经冷却至-2℃可消除进餐刺激引起的血浆胃泌素和生长抑素升高。阿托品不改变胃泌素对冷却的反应，但氨甲酰甲胆碱可将抑制幅度降至37%±9%，且不影响血浆生长抑素。在迷走神经阻断期间，胃泌素释放肽可使餐后血浆胃泌素升高至与迷走神经完整时相当的水平，但不改变血浆生长抑素的最低反应。冷却至-2℃同样可抑制与胰岛素低血糖相关的血浆胃泌素和生长抑素升高。冷却至12℃可选择性阻断迷走神经抑制通路，对进餐刺激的胃泌素释放无影响，并部分降低血浆胃泌素对胰岛素低血糖的反应。因此，食物和胰岛素低血糖引起的胃泌素释放是由迷走神经非毒蕈碱兴奋性通路介导的，该通路独立于循环血浆生长抑素的变化，但可能包括候选神经递质胃泌素释放肽的参与。
