Onaga T, Harada Y, Okamoto K
Veterinary Physiology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
Regul Pept. 1998 Oct 16;77(1-3):69-76. doi: 10.1016/s0167-0115(98)00046-9.
This study examined the effect of intravenous infusion of pituitary adenylate cyclase-activating polypeptide (PACAP) on duodenal motility in sheep and the mechanism of the action of PACAP. The bilateral cervical vagus nerves were coiled with a cooling device under anesthesia. Duodenal motility was recorded by manometry in conscious animals. PACAP-27, PACAP-38 and vasoactive intestinal polypeptide (VIP) were infused intravenously at 3, 10, 30 and 100 pmol/kg in phase II of the duodenal migrating motor complexes (MMC). PACAP-27 induced a cluster of phasic contractions of the duodenum, while PACAP-38 only augmented the spontaneous contractions. The pattern of PACAP-27-induced contractions was different from that of phase III of MMC, and the contractions were followed by a quiescence period. VIP at only the highest dose induced phase III-like activity of the duodenum. Both the intravenous background infusion of atropine at 10 nmol/kg/min and the reversible cooling blockade of the bilateral cervical vagus nerves blocked the effect of PACAP-27. The application of PACAP-27 at concentrations ranging from 10 nM to 1 microM did not induce contractions of ovine duodenal smooth muscles. These results indicate that PACAP contracts the ovine duodenum via the vagal cholinergic efferent fibers, suggesting that PACAP acts on the central nervous system.
本研究检测了静脉输注垂体腺苷酸环化酶激活多肽（PACAP）对绵羊十二指肠运动的影响及其作用机制。在麻醉状态下，用冷却装置盘绕双侧颈迷走神经。通过压力测定法记录清醒动物的十二指肠运动。在十二指肠移行性运动复合波（MMC）的II期，以3、10、30和100 pmol/kg的剂量静脉输注PACAP-27、PACAP-38和血管活性肠肽（VIP）。PACAP-27诱发十二指肠出现一阵相性收缩，而PACAP-38仅增强自发收缩。PACAP-27诱发的收缩模式不同于MMC的III期，且收缩后有一段静息期。仅最高剂量的VIP诱发十二指肠出现类似III期的活动。以10 nmol/kg/min的剂量静脉持续输注阿托品以及双侧颈迷走神经的可逆性冷却阻断均阻断了PACAP-27的作用。应用浓度范围为10 nM至1 microM的PACAP-27未诱发绵羊十二指肠平滑肌收缩。这些结果表明，PACAP通过迷走胆碱能传出纤维使绵羊十二指肠收缩，提示PACAP作用于中枢神经系统。
