van Wyk M, Sommers D K, Moncrieff J
Department of Pharmacology, University of Pretoria, South Africa.
Digestion. 1993;54(1):40-3. doi: 10.1159/000201009.
This study examines the influence of the serotonergic system on the effect of metoclopramide on gastric emptying. Six subjects received the following pretreatments before metoclopramide and paracetamol: fluoxetine (5-HT uptake inhibitor); meterogoline (5-HT1 antagonist); pizotifen (5-HT2 antagonist) or methysergide (5-HT1 and 5-HT2 antagonist). One regimen consisted of metoclopramide (5-HT3 antagonist and 5-HT4 agonist) alone. Gastric emptying was measured by the mean cumulative fraction absorbed-time profiles of paracetamol. Methysergide/metoclopramide significantly delayed gastric emptying from 30 min onwards. Metoclopramide with either metergoline or pizotifen did not retard gastric emptying to the same extent, suggesting a greater influence with simultaneous 5-HT1 and 5HT2 blockade. Metoclopramide/fluoxetine caused a significant decrease in the fractional absorption of paracetamol at 5 min when compared to the metoclopramide regimen. It was assumed that the influence of metoclopramide was not optimal at this stage, therefore possibly indicating domination of 5-HT3 over 5-HT4 effects, resulting in gastric delay. It therefore seems as if all the 5-HT receptors present in the gut have a role to play in the control of gastric emptying.
本研究考察了血清素能系统对胃复安胃排空作用的影响。6名受试者在服用胃复安和对乙酰氨基酚前接受了以下预处理：氟西汀（5-羟色胺摄取抑制剂）；米替戈林（5-羟色胺1拮抗剂）；苯噻啶（5-羟色胺2拮抗剂）或美西麦角（5-羟色胺1和5-羟色胺2拮抗剂）。一种方案仅包含胃复安（5-羟色胺3拮抗剂和5-羟色胺4激动剂）。通过对乙酰氨基酚的平均累积吸收分数-时间曲线来测量胃排空。从30分钟起，美西麦角/胃复安显著延迟了胃排空。胃复安与米替戈林或苯噻啶联用并未在同等程度上延迟胃排空，这表明5-羟色胺1和5-羟色胺2同时被阻断时影响更大。与单独使用胃复安的方案相比，胃复安/氟西汀在5分钟时使对乙酰氨基酚的吸收分数显著降低。据推测，此时胃复安的作用并非最佳，因此可能表明5-羟色胺3的作用强于5-羟色胺4，从而导致胃排空延迟。因此，肠道中存在的所有5-羟色胺受体似乎都在胃排空的控制中发挥作用。
