Brikas P
Laboratory of Physiology, Veterinary Faculty, Aristotelian University, Thessaloniki, Greece.
Zentralbl Veterinarmed A. 1990 Sep;37(8):577-84. doi: 10.1111/j.1439-0442.1990.tb00947.x.
The role of central and peripheral alpha-adrenoceptors in regulation of ileal, caecal and proximal colonic myoelectrical activity was studied in five conscious ewes chronically fitted with intraparietal electrodes and a cannula in a lateral ventricle of the brain. About 5 min after the end of a regular spiking activity (RSA) phase of a migrating motor complex (MMC) in the distal ileum, selective alpha 2- and alpha 1-agonists and antagonists were administered intravenously (i.v.) or intracerebroventricularly (i.c.v.). The alpha 2-antagonist yohimbine (600 micrograms/kg i.v. or 60 micrograms/kg i.c.v.) induced an RSA phase in the ileum. The alpha 2-agonist naphazoline (30 micrograms/kg i.v. or 3 micrograms/kg i.c.v.) stopped or greatly reduced the frequency of caecal and proximal colonic contractions, respectively, and prevented any MMC in the ileum, effects which were abolished when the animals were either i.v. or i.c.v. pretreated with yohimbine. The alpha 1-antagonist prazosin (600 micrograms/kg i.v., but not 60 micrograms/kg i.c.v.) selectively reduced the frequency of contractions in the cranial caecum and proximal colon. The alpha 1-agonist phenylephrine (40 micrograms/kg i.v., but not 4 micrograms/kg i.c.v.) provoked an RSA phase in the ileum, decreased the frequency of contractions in the blind pole and the middle of the caecum and increased that in the cranial caecum and the proximal colon. These effects of phenylephrine were blocked by i.v., but not i.c.v., prazosin. The present results suggest that alpha-adrenoceptors are involved in the control of the intestinal motility as follows: I) central alpha 2-inhibitory and peripheral alpha 1-excitatory receptors for the ileum, II) central and peripheral alpha 2- and peripheral alpha 1-inhibitory receptors for the blind pole and the middle of caecum and III) central and peripheral alpha 2-inhibitory and peripheral alpha 1-excitatory receptors for the cranial caecum and the proximal colon.(ABSTRACT TRUNCATED AT 250 WORDS)
在五只长期植入脑室内套管及腹壁电极的清醒母羊身上，研究了中枢和外周α-肾上腺素能受体对回肠、盲肠及近端结肠肌电活动的调节作用。在回肠远端移行性运动复合波（MMC）的规则锋电活动（RSA）阶段结束约5分钟后，经静脉（i.v.）或脑室内（i.c.v.）给予选择性α2和α1激动剂及拮抗剂。α2拮抗剂育亨宾（静脉注射600微克/千克或脑室内注射60微克/千克）可诱发回肠的RSA阶段。α2激动剂萘甲唑啉（静脉注射30微克/千克或脑室内注射3微克/千克）分别使盲肠和近端结肠的收缩频率停止或大幅降低，并阻止回肠出现任何MMC，当动物预先经静脉或脑室内注射育亨宾后，这些作用即被消除。α1拮抗剂哌唑嗪（静脉注射600微克/千克，但脑室内注射60微克/千克无效）可选择性降低盲肠头部和近端结肠的收缩频率。α1激动剂去氧肾上腺素（静脉注射40微克/千克，但脑室内注射4微克/千克无效）可诱发回肠的RSA阶段，降低盲肠盲端和中部的收缩频率，并增加盲肠头部和近端结肠的收缩频率。去氧肾上腺素的这些作用可被静脉注射的哌唑嗪阻断，但不能被脑室内注射的哌唑嗪阻断。目前的结果表明，α-肾上腺素能受体参与肠道运动的控制如下：I）回肠的中枢α2抑制性和外周α1兴奋性受体；II）盲肠盲端和中部的中枢和外周α2及外周α1抑制性受体；III）盲肠头部和近端结肠的中枢和外周α2抑制性及外周α1兴奋性受体。（摘要截选至250字）
