Hoang T V, Choe E U, Burgess R S, Cork R C, Flint L M, Ferrara J J
Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112, USA.
J Pediatr Surg. 1996 Dec;31(12):1659-62. doi: 10.1016/s0022-3468(96)90042-1.
To characterize neonatal mesenteric alpha-adrenoceptor populations, an extracorporeal perfusion circuit was established to control intestinal blood flow in prematurely delivered (by cesarean section at 90% of gestational age) piglets. Activation of alpha 1-adrenoceptors was documented by observing dose-dependent increases in mesenteric perfusion pressure after intramesenteric arterial injection of methoxamine; alpha 2-adrenoceptor activity was confirmed by finding similar increases in mesenteric perfusion pressure after intramesenteric arterial injections of BHT 933. Peripheral intravenous injections of WB 4101 (a competitive alpha 1A-adrenoceptor antagonist), but not clorethylclonidine (CEC, an alpha 1B-adrenoceptor antagonist), significantly blunted (P < .05, ANOVA) the mesenteric vasoconstrictor responses to methoxamine. The mesenteric vasoconstrictor response to BHT 933 (an alpha 2-adrenoceptor agonist) also was blunted by WB 4101, but not by CEC. These data suggest that alpha 1A- and alpha 2-adrenoceptors can be activated in the small intestinal mesentery of piglets well before they reach full-term maturation, although receptor specificity has not been fully established.
为了描述新生仔猪肠系膜α-肾上腺素能受体群体的特征，建立了一个体外灌注回路来控制早产（在妊娠90%时剖宫产）仔猪的肠血流量。通过观察肠系膜内动脉注射甲氧明后肠系膜灌注压的剂量依赖性增加来证明α1-肾上腺素能受体的激活；通过在肠系膜内动脉注射BHT 933后发现肠系膜灌注压有类似增加来证实α2-肾上腺素能受体的活性。外周静脉注射WB 4101（一种竞争性α1A-肾上腺素能受体拮抗剂），而非氯乙基可乐定（CEC，一种α1B-肾上腺素能受体拮抗剂），显著减弱了（P <.05，方差分析）肠系膜对甲氧明的血管收缩反应。肠系膜对BHT 933（一种α2-肾上腺素能受体激动剂）的血管收缩反应也被WB 4101减弱，但未被CEC减弱。这些数据表明，在仔猪达到足月成熟之前，α1A-和α2-肾上腺素能受体就可以在其小肠系膜中被激活，尽管受体特异性尚未完全确立。
