Penagini Roberto, Carmagnola Stefania, Cantù Paolo, Allocca Mariangela, Bianchi Paolo A
Cattedra di Gastroenterologia, Dipartimento di Scienze Mediche, University of Milan, Italy.
Gastroenterology. 2004 Jan;126(1):49-56. doi: 10.1053/j.gastro.2003.10.045.
The role of fundic tension and stretch mechanoreceptors in triggering transient lower esophageal sphincter (LES) relaxation is still unknown. This information would be useful for the development of effective pharmacologic strategies. To elucidate this topic, gastric contractile activity was modified during isovolumetric gastric distention at 2 different volumes.
LES (Dentsleeve) and gastric (barostat) motility were recorded in 21 healthy subjects during studies comprising two 30-minute isovolumetric gastric distentions (placebo and glucagon or erythromycin). Glucagon (bolus of 4.8 microg/kg plus infusion of 9.6 microg x kg(-1) x h(-1)) was administered at high intragastric volume (i.e., 75% of the threshold volume for discomfort; n = 7) and erythromycin (3 mg/kg) at high (n = 7) and low intragastric volume (i.e., at perception threshold; n = 7).
Glucagon decreased (P < 0.05) baseline intragastric pressure and abolished gastric contractions (0 vs. 16.7 +/- 2.3), whereas erythromycin increased (P < 0.05) baseline pressure and doubled (P < 0.05) the rate of gastric contractions at both volumes. Neither drug affected the rate of transient LES relaxations. Low intragastric volume induced a lower rate of transient LES relaxations (1.7 +/- 0.3 vs. 5.7 +/- 1.1; P < 0.01) and gastric contractions (11.8 +/- 2.5 vs. 20.5 +/- 3.1; P < 0.05) compared with high volume but similar baseline intragastric pressure (10.6 +/- 0.6 vs. 11.9 +/- 0.9 mm Hg).
Stretch receptors (gastric volume) seem to be more relevant than tension receptors in triggering transient LES relaxation.
胃底张力和牵张机械感受器在触发食管下括约肌（LES）瞬时松弛中的作用尚不清楚。该信息对于开发有效的药物策略将是有用的。为阐明这一主题，在两种不同容量的等容胃扩张期间改变胃收缩活动。
在包含两次30分钟等容胃扩张（安慰剂和胰高血糖素或红霉素）的研究中，记录了21名健康受试者的LES（Dentsleeve）和胃（气压计）运动。在高胃内体积（即不适阈值体积的75％；n = 7）时给予胰高血糖素（4.8μg/kg推注加9.6μg×kg-1×h-1输注），在高（n = 7）和低胃内体积（即在感知阈值；n = 7）时给予红霉素（3mg/kg）。
胰高血糖素降低（P <0.05）基线胃内压并消除胃收缩（0对16.7±2.3），而红霉素在两种体积下均增加（P <0.05）基线压力并使胃收缩率加倍（P <0.05）。两种药物均未影响LES瞬时松弛率。与高体积相比，低胃内体积诱导较低的LES瞬时松弛率（1.7±0.3对5.7±1.1；P <0.01）和胃收缩率（11.8±2.5对20.5±3.1；P <0.05），但基线胃内压相似（10.6±0.6对11.9±0.9mmHg）。
在触发LES瞬时松弛方面，牵张感受器（胃体积）似乎比张力感受器更重要。
