TY - JOUR
T1 - Role of alpha-2 adrenoceptors in regulation of giant migrating contractions and defecation in conscious dogs
AU - Nagao, Munenori
AU - Shibata, Chikashi
AU - Funayama, Yuji
AU - Fukushima, Kouhei
AU - Takahashi, Ken Ichi
AU - Jin, Xue Lin
AU - Kudoh, Katsuyoshi
AU - Sasaki, Iwao
N1 - Funding Information:
This study was presented at 19th International Symposium on Neuro-gastroenterology and Motility in Barcelona, Spain, in October 2003. This study was supported by a Grant-in-aid from Japan Society for the Promotion of Science (NO. 13671277).
PY - 2007/9
Y1 - 2007/9
N2 - The aim was to investigate the effects of α2-adrenoceptor antagonsist yohimbine on colonic motility and defecation. The effects of yohimbine (0.5, 1.0, and 3.0 mg/kg) on colonic motility and defecation were studied in neurally intact dogs (N=6), dogs with extrinsic denervation of the ileocolon (N=4), and dogs with enterically isolated ileocolnic loops (N=5) equipped with strain gauge force transducers on the ileocolon. The effects of yohimbine on colonic motility and defecation were also studied in the presence of various antagonists (atropine, hexamethonium, ondansetron, FK224, and naloxone). Yohimbine evoked giant migrating contractions and defecation in a dose-independent manner in neurally intact dogs. These stimulatory effects of yohimbine were abolished by atropine and hexamethonium. In dogs with extrinsic denervation, yohimbine induced giant migrating contractions in the colon but did not stimulate defecation. In dogs with ileocolonic loops, yohimbine induced colonic motor complexes but not giant migrating contractions in the enterically isolated colon. These results indicate that α2-adrenoceptors in the peripheral nervous system regulate giant migrating contractions by controlling the release of acetylcholine, while those in the central nervous system must be important in the regulation of defecation.
AB - The aim was to investigate the effects of α2-adrenoceptor antagonsist yohimbine on colonic motility and defecation. The effects of yohimbine (0.5, 1.0, and 3.0 mg/kg) on colonic motility and defecation were studied in neurally intact dogs (N=6), dogs with extrinsic denervation of the ileocolon (N=4), and dogs with enterically isolated ileocolnic loops (N=5) equipped with strain gauge force transducers on the ileocolon. The effects of yohimbine on colonic motility and defecation were also studied in the presence of various antagonists (atropine, hexamethonium, ondansetron, FK224, and naloxone). Yohimbine evoked giant migrating contractions and defecation in a dose-independent manner in neurally intact dogs. These stimulatory effects of yohimbine were abolished by atropine and hexamethonium. In dogs with extrinsic denervation, yohimbine induced giant migrating contractions in the colon but did not stimulate defecation. In dogs with ileocolonic loops, yohimbine induced colonic motor complexes but not giant migrating contractions in the enterically isolated colon. These results indicate that α2-adrenoceptors in the peripheral nervous system regulate giant migrating contractions by controlling the release of acetylcholine, while those in the central nervous system must be important in the regulation of defecation.
KW - Defecation
KW - Extrinsic denervation
KW - Giant migrating contractions
KW - Ileocolonic loop
KW - Yohimbine
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U2 - 10.1007/s10620-006-9154-9
DO - 10.1007/s10620-006-9154-9
M3 - Article
C2 - 17429732
AN - SCOPUS:34547851740
VL - 52
SP - 2204
EP - 2210
JO - Digestive Diseases and Sciences
JF - Digestive Diseases and Sciences
SN - 0163-2116
IS - 9
ER -