[Effects of intra-amygdaloid injection of motilin on the interdigestive migrating myoelectrical complex in rat].
OBJECTIVE
This study is undertaken to explore the effects of motilin in the amygdaloid nucleus on the interdigestive migrating myoelectrical complex (MMC) in rats.


METHODS
Adult SD rats of either sex were used. 0.5 microL motilin (0.74 nmol/microL) was injected into the guide cannula which had been stereotaxically implanted into the amygdaloid nucleus. Then the MMC was recorded by an RM6240B multilead physiological recording system. Some rats also received subdiaphragmatic vagotomy, or intravenous injection of the M-cholinergic receptor antagonist atropine (50 microg/kg), the alpha-adrenergic receptor antagonist phentolamine (200 microg/kg), the beta-adrenergic receptor antagonist propranolol (100 microg/kg), the anti-motilin serum.


RESULTS
After motilin was injected into the amygdaloid nucleus, the duodenal MMC cycle duration was decreased significantly, (586.3 +/- 42.0) vs. (694.0 +/- 36.2)s. However, the amplitude of phase III and the frequency of phase III was increased, (294.7 +/- 43.2) vs (255.1 +/- 23.5) microV and (23.1 +/- 0.6) vs. (18.2 +/- 0.4) bursts/min. But there were no effects on the duration of phase III. The percentage change in frequency of phase III was much greater than the percentage change in amplitude of phase III, (54.3 +/- 5.6) vs. (22.4 +/- 4.3). The effects of motilin in the amygdaloid nucleus on MMC were completely abolished by subdiaphragmatic vagotomy. The effects of motilin in the amygdaloid nucleus on MMC were not affected by intravenously injected atropine, phentolamine or propranolol. The anti-motilin serum partly abolished the effects of motilin in the amygdaloid nucleus on MMC.


CONCLUSIONS
Motilin in the amygdaloid nucleus has effects on the duodenal MMC cycle duration, the amplitude of phase III and the frequency of phase III, all of which may rely on either the effects of noncholinergic and nonadrenergic neurons on duodenal smooth muscle, or the increase of local motilin via nucleus amygdalae-hypothalamus-brain stem-vagus pathway.
Liu
Mei
M
Department of Gastroenterology, Second Hospital of Xi' an Jiaotong University, Xi'an 710004, China.
Li
Feng-hua
FH
Dong
Lei
L
Zhu
Wen-yi
WY
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004386:Duodenum / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008297:Male; D008845:Microinjections; D009037:Motilin / Q000494:pharmacology*; D016065:Myoelectric Complex, Migrating / Q000187:drug effects*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D009037:Motilin