ABSTRACT
Objective To investigate the effect and mechanism of Ghrelin on the contraction and relaxation of rat small intestinal smooth muscle. Methods The effect of different concentrations of Ghrelin (0;20;40;80 μg/kg) on the small intestinal transit in vagotomized rats in vivo and Ghrelin (0.01; 0.1;0.5 ; 1.0 μmol/L) on the contraction and relaxation of rat small intestinal smooth muscle strips in vitro was observed,the locations of Ghrelin receptors (GHS-R1 a) in small intestinal muscle layers were detected by immunofluorescency. Results Ghrelin dose-dependently increases small intestinal transit (( 25.4 ± 1.0)％,(33.7 ± 1.9)％,(39.3 ±2.4)％,(44.7 ±2.1)％),enhances the contraction ((67.0 ±2.4)％,(149.5 ±3.3)％,(187.1 ±4.7)％,(213.5 ±3.4)％) and relaxation ((35.3 ± 1.1)％,(62.9 ± 3.8 ) ％,( 79.6 ± 2.7 ) ％,( 94.6 ± 2.2 ) ％ ) of smooth muscle strips mediated by carbachol.Ghrelin receptors were mainly located on membrane of the nerve cells in the muscle layers,while no receptors exist on membrane of smooth muscle cells. Conclusions Ghrelin enhances the effect of contraction and relaxation of rat small intestinal smooth muscle mediated by cholinergic neurotransmitters activating nerve cells in the enteric plexus.
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Objective To investigate the effects of ghrelin on colonic motility in mice.Methods The eflfects of ghrelin on colonic propulsive movement were detected by charcoal suspension pushing test after injection of normal saline and different doses of ghrelin(20,50,100,200 ng/g).The effects of atropine,NG-nitro-L-arginine methylester hydrochloride(L-NAME)or D-Lys3-GHRP-6 on the changes of colonic propulsive movement caused by ghrelin(100 ng/g)were also investigated.In vitro,the effects of different doses of ghrelin(0.01,0.1,1,10μmol/L)on the spontaneous contraction amplitude of proximal colonic circular muscle strips were studied.Results Ghrelin significantly accelerated the colonic propulsive movement in dose-dependent manner,but the efiect was significantly inhibited in the presence of atropine,L-NAME or D-Lys3-GHRP-6(t=10.230,12.560,11.590,P＜0.05).Administration of ghrelin significantly increased the contraction amplitude of colonic circular muscle strips.but this effect was inhibited when the colonic circular muscle strips were pretreated by tetrodotoxin.ConclusionsGhrelin can accelerate colonic propulsive movement by activating growth hormone secretagogue receptor of cholinergic excitatory pathways and nitrergic nervous pathways in the enteric nervous system of colon.
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Objective:To investigate colonic motility effect and mechanism of Ghrelin in diabetic mice.Methods:In vivo,the effects of Ghrelin(50,100,200 ?g/kg)on colonic transit of diabetic mice were measured by charcoal suspension pushing test.The effects of Atropine,N?-nitro-L-arginine methylester hydrochloride(L-NAME)and D-Lys3-GHRP-6(GHS-R antagonist)on the colonic transit of Ghrelin(200 ?g/kg)were also investigated.In vitro,the effects of Ghrelin on spontaneous contraction of proximal colonic circular muscle strips of diabetic mice were studied.Results:Ghrelin accelerated colonic transit of diabetic mice with significant dose-response relationship(P
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Objective To evaluate the clinical significance of the intraoperative detection of peritoneal micrometastases of gastric cancer.Methods In selected 50 cases of gastric cancer in which no obvious peritoneal metastasis was found preoperatively or during laparotomy,Douglas′s pouch peritoneal biopsy was undertaken intraoperatively,then HE and CK-20 immunohistochemistry staining of the specimens was performed.The expression of CK-20 mRNA in peritoneal irrigation fluid was also determined by RT-PCR.Results HE staining of all cases was negative.The positive rate of CK-20 immunohistochemistry staining was 24.0 %(12/50),and 36.0 %(18/50) with RT-PCR method.The positive rate of CK-20 mRNA was significantly related with the histological type,the depth of invasion and the number of lymph node metastasis(P