Effects of motilin and ursodeoxycholic acid on gastrointestinal myoelectric activity of different origins in fasted rats.
OBJECTIVE
To investigate gastrointestinal migrating myoelectric complex (MMC) and the effects of porcine motilin and ursodeoxycholic acid (UDCA) on MMC of gastrointestinal tract of different origins in fasted rats.


METHODS
Three bipolar silver electrodes were chronically implanted on the antrum, duodenum and jejunum. Seven days later 24 experimental rats were divided into 2 groups. One group was injected with porcine motilin via sublingual vein at a dose of 20 microg/kg, the other group was perfused into stomach with UDCA. The gastrointestinal myoelectric activity was recorded 1 h before and 2 h after the test substance infusions into the rats.


RESULTS
In all fasted rats a typical pattern of MMC was observed. Among the totally 68 activity fronts recorded in fasted rats under control, 67% started in duodenum, and 33% in antrum. MMC cycle duration and duration of phase III of antral origin were longer than those of duodenal origin. Administration of 20 microg/kg porcine motilin induced a premature antral phase III of antral origin. But perfusion into stomach with UDCA resulted in shorter MMC cycle duration, longer duration of phase III of duodenal origin, which were followed with shorter cycle duration and duration of antral phase III.


CONCLUSIONS
In fasted rats, MMC could originate from antrum and duodenum respectively. The characteristics of MMC of different origins may contribute to the large variations within subjects. The mechanisms of different origins of phase III may be different. Porcine motilin and UDCA could affect MMC of different origins of the gastrointestinal tract in fasted state, respectively.
Department of Gastroenterology, Second Hospital of Xi'an Jiaotong University, Xi'an 710004, Shaanxi Province, China.
Ping
P
Fang
Lei
L
Dong
Jin-Yan
JY
Luo
Xiao-Long
XL
Wan
Ke-Xin
KX
Du
Ning-Li
NL
Chai
D000818:Animals; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D003243:Consciousness; D004567:Electrodes, Implanted; D005215:Fasting / Q000502:physiology; D005260:Female; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D008297:Male; D009037:Motilin / Q000494:pharmacology*; D016065:Myoelectric Complex, Migrating / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine; D014580:Ursodeoxycholic Acid / Q000494:pharmacology*
D002756:Cholagogues and Choleretics; D005765:Gastrointestinal Agents; D009037:Motilin; D014580:Ursodeoxycholic Acid