Onaga T, Nagashima C, Sakata T
Veterinary Physiology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
J Comp Physiol B. 2000 Sep;170(5-6):469-79. doi: 10.1007/s003600000125.
The present study evaluated the role of nitric oxide in the regulation of duodenal motility and pancreatic exocrine secretion in conscious sheep. Intravenous infusions of nitric oxide synthase inhibitors, Nomega-nitro-L-arginine-methyl ester (L-NAME) and Nomega-nitro-L-arginine, induced clusters of duodenal contractions like phase III of migrating motor complexes and simultaneously inhibited flow rate, bicarbonate ion and enzyme outputs of pancreatic juice. The effects of L-NAME were inhibited by simultaneous infusion of L-arginine, but not altered by adrenergic blockade using a combined infusion of phentolamine and propranolol. Inhibition of the pancreatic secretion occurred in coincidence with initiation of the duodenal contractions, while the pancreatic secretion was not inhibited when the premature duodenal contractions were abolished by the L-arginine infusion. The initiation of the cluster of duodenal contractions by L-NAME was not abolished by background infusion of atropine, whereas the amplitude of contractions was significantly inhibited by atropine. These results suggest that intrinsic nitric oxide plays a crucial role in the regulation of duodenal tone and maintenance of continuous secretion by the exocrine pancreas in sheep. These results also implied that inhibition of pancreatic exocrine secretion by the nitric oxide synthase inhibitor is presumably mediated in part through the contractile effect on the duodenum.
本研究评估了一氧化氮在清醒绵羊十二指肠运动调节和胰腺外分泌中的作用。静脉输注一氧化氮合酶抑制剂N-甲基-L-精氨酸甲酯（L-NAME）和N-硝基-L-精氨酸，可诱发十二指肠收缩簇，类似移行运动复合波的第三相，同时抑制胰液的流速、碳酸氢根离子和酶的分泌量。同时输注L-精氨酸可抑制L-NAME的作用，但联合输注酚妥拉明和普萘洛尔进行肾上腺素能阻断时，其作用未改变。胰腺分泌的抑制与十二指肠收缩的开始同时发生，而当L-精氨酸输注消除过早的十二指肠收缩时，胰腺分泌未受抑制。L-NAME引发的十二指肠收缩簇不被阿托品的背景输注所消除，而阿托品可显著抑制收缩幅度。这些结果表明，内源性一氧化氮在绵羊十二指肠张力调节和胰腺外分泌持续分泌的维持中起关键作用。这些结果还暗示，一氧化氮合酶抑制剂对胰腺外分泌的抑制作用可能部分是通过对十二指肠的收缩作用介导的。
