OBJECTIVETo investigate the effect and mechanism of ghrelin and its synthetic peptide GHRP-6 on gastric motor in mice.

METHODSIn vivo, the dose-dependent effects of ghrelin (20,50,100,200 mug/kg) and GHRP-6 (20,50,100,200 mug/kg) on gastric emptying were measured by intragastric application of phenol red test which was adapted for use in mice. The effects of atropine, NG-nitro-L-arginine methyl ester (L-NAME), and D-Lys(3)-GHRP-6 (GHS-R antagonist) on the gastric motor induced by ghrelin and GHRP-6 (100 mug/kg) were also investigated. In vitro, the effects of ghrelin (0.01,0.1,1.0,10.0 mumol/L) and GHRP-6 (0.01,0.1,1.0,10.0 mumol/L) on spontaneous contraction of mice fundic muscle strips were studied as well.

RESULTSBoth ghrelin (50,100,200 mug/kg) and GHRP-6 (50,100,200 mug/kg) significantly accelerated gastric emptying (P<0.05), but they failed to accelerate gastric emptying in the presence of atropine, L-NAME and D-Lys(3)-GHRP-6 (P<0.05). Ghrelin (0.1, 1.0, 10.0 mumol/L) and GHRP-6 (0.1, 1.0, 10.0 mumol/L) induced significant contraction of fundic muscle strips in concentration-dependent manner (P<0.05), which could be blocked by tetrodotoxin.

CONCLUSIONGhrelin and its synthetic peptide GHRP-6 accelerate gastric emptying perhaps by activating GHS-R of cholinergic excitatory pathways and nitrergic nervous pathways in the enteric nervous system.

Animals ; Female ; Gastric Emptying ; drug effects ; Ghrelin ; pharmacology ; Male ; Mice ; Mice, Inbred C57BL ; Oligopeptides ; pharmacology ; Stomach ; drug effects ; physiology

OBJECTIVETo investigate regulative effect of electroacupuncture (EA) of different frequencies on derangement of gastric electric rhythm in rabbits.

METHODSDerangement of gastric electric rhythm model was made with injection of erythromycin into ear vein in 40 rabbits, and randomly divided into a model group, a 3 Hz-EA group, a 20 Hz-EA group and a 100 Hz-EA group. They were treated with EA at Zusanli (ST 36) with 3 Hz, 20 Hz and 100 Hz, respectively. PDP and PTP at different periods were detected with IEGG spectrum analyzer.

RESULTSErythromycin could significantly enhance PDP and PTP values in the rabbit (P < 0.001). PDP and PTP values were reduced significantly after EA with 3 Hz, 20 Hz and 100 Hz (P < 0.05), with no significant differences in effect on PDP among them (P > 0.05); therapeutic effect of the EA of 20 Hz on PTP was better than that of 3 Hz (P < 0.05), with no significant difference as compared with the EA of 100 Hz.

CONCLUSIONEA of the 3 frequencies shows significantly different regulative effects on derangement of gastric electric rhythm in rabbits.

Animals ; Electroacupuncture ; Erythromycin ; pharmacology ; Female ; Gastrointestinal Motility ; drug effects ; Male ; Rabbits ; Stomach ; physiology

Animals ; Cholagogues and Choleretics ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Gardenia ; chemistry ; In Vitro Techniques ; Muscle Contraction ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; Rabbits ; Stomach ; drug effects

This study is to observe the difference in pharmacological characteristics between circular smooth muscles of rat isolated gastric body and gastric fundus, and to investigate the effects of nucleoside and nucleotide on circular smooth muscle of the rat gastric body and the involved receptors. Circular muscle strips of the rat gastric body and gastric fundus were prepared, and contractile responses to agonists were investigated with a technique of drug-receptor interaction in functional system. There was no significant difference between the circular muscle strips of the gastric body and gastric fundus in the responses to KCl, and no difference in EC50 values of contractile responses for 5-HT and His between the two kinds of preparations (P > 0.05). However, Emax values of contractile responses to 5-HT and His [(0.81 +/- 0.26) and (0.88 +/- 0.27) g] in gastric body were significantly smaller than those in gastric fundus [(2.67 +/- 0.61) and (1.90 +/- 0.68) g, P < 0.01], and EC50 value of CCh produced contractile response [(0.45 +/- 0.15) micromol x L(-1)] in gastric body was significantly higher than that in gastric fundus [(0.20 +/- 0.09) micromol x L(-1), P < 0.01]. In precontracted circular muscle strips of the gastric body, ATP (0.1-3000 micromol x L(-1)) produced only a contractile response concentration-dependently, but the same concentration of ATP induced a biphasic response (relaxation followed by a contraction) in precontracted circular muscle strips of the gastric fundus. ATP, UTP, ADP, 2-MeSATP and alpha,beta-MeATP produced contractile responses concentration-dependently in circular muscle strips of the rat gastric body. The EC50 value for 2-MeSATP [(7.2 +/- 5.2) nmol x L(-1)] was about 500 times lower than that for Ach [(3.47 +/- 1.20) micromol x L(-1)]. The rank order of potency for the contraction was 2-MeSATP>ADP>ATP=UTP>alpha,beta-MeATP>adenosine. The contractile responses to ATP and UTP were not significantly affected by phentolamine, propranolol, atropine or tetrodotoxin. In conclusion, there is a significant difference in pharmacological characteristics between the circular smooth muscles of the rat gastric body and gastric fundus and nucleotides might be important mediators responsible for the contraction via a specific P2Y receptor in circular smooth muscle of the rat gastric body.
Adenosine ; pharmacology ; Adenosine Diphosphate ; pharmacology ; Adenosine Triphosphate ; analogs & derivatives ; pharmacology ; Animals ; Gastric Fundus ; drug effects ; physiology ; Male ; Muscle Contraction ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; Purinergic P2 Receptor Agonists ; Rats ; Rats, Wistar ; Receptors, Purinergic P2 ; drug effects ; Stomach ; drug effects ; physiology ; Thionucleotides ; pharmacology ; Uridine Triphosphate ; pharmacology

OBJECTIVETo investigate the effects of hepatocyte growth factor (HGF) on adriamycin-induced apoptosis of gastric cancer cells in vitro.

METHODSAn eukaryotic expression plasmid (pIRES2-EGFP) containing HGF (pIRES2-EGFP-HGF) was constructed. Human gastric cancer cell line MKN-45 cells were transfected in vitro with pIRES2-EGFP containing HGF or not. RT-PCR and Western blot were used to determine the target gene expression. Function of HGF was determined by MDCK cell scattering assay. Cell viability was tested by MTT assay. Apoptosis was evaluated by DNA fragmentation assay as well as flow cytometry using PI staining.

RESULTSThe HGF transfected MKN45 cells could stably express HGF mRNA, and secrete HGF protein to the cell culture median which was detected to exhibit normal function. The cell inhibition rate induced by adriamycin in HGF-transfected cells was decreased as compared to that of parental and mock transfected cells. When treated with adriamycin at 0.1 microg/ml, the parental and mock transfected cells present typical apoptotic ladder on DNA electrophoresis while HGF transfected cell did not. The apoptotic rate was decreased in HGF transfected cells as compared with that of parental and mock transfected cells.

CONCLUSIONHGF gene transfection may suppress adriamycin-induced apoptosis of gastric cancer cells.

Antibiotics, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; genetics ; physiology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; genetics ; physiology ; DNA Fragmentation ; drug effects ; Dose-Response Relationship, Drug ; Doxorubicin ; pharmacology ; Flow Cytometry ; Green Fluorescent Proteins ; genetics ; metabolism ; Hepatocyte Growth Factor ; genetics ; metabolism ; physiology ; Humans ; Plasmids ; genetics ; RNA, Messenger ; genetics ; metabolism ; Recombinant Fusion Proteins ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Transfection

OBJECTIVETo investigate the role of caspase-8 in vitamin E succinate (VES)-induced apoptosis in human gastric carcinoma cells.

METHODSThe expression and activity of caspase-8 were measured by the Western Blot method with fluorescence and DAPI staining.

RESULTSVES treatment induced the expression and activity of caspase-8 in a dose-dependent manner; the apoptosis ratio induced by VES was significantly decreased in SGC-7901 cells treated with caspase-8 inhibitor.

CONCLUSIONCaspase-8 plays an important role in SGC-7901 cell apoptosis induced by VES.

Apoptosis ; drug effects ; Caspase 8 ; Caspases ; metabolism ; physiology ; Dose-Response Relationship, Drug ; Humans ; Stomach Neoplasms ; enzymology ; pathology ; Tocopherols ; Tumor Cells, Cultured ; Vitamin E ; analogs & derivatives ; pharmacology

Women often complain gut symptoms during pregnancy and the luteal phase of the menstrual cycle. To investigate the relationship between ovarian steroids and the abnormal gut motility and sensitivity, the expressions of cholecystokinin (CCK), calcitonin gene-related peptide (CGRP) and their receptors in stomach were studied in ovariectomized rats. Blood samples were collected for estradiol (E(2)), progesterone (P(4)), CCK and CGRP radioimmunoassay. Expression of CCK(A) receptor in fundus was assessed by Western blot and CGRP receptor was determined by (125)I-CGRP radioligand binding assay (RBA). The replacement therapy with estradiol benzoate (EB) could dose-dependently increase the plasma CCK level and the expression of gastric CCK(A) receptor (P<0.05 respectively). P(4) replacement therapy could stimulate the release of CGRP and increase the binding sites of CGRP receptors in stomach (P<0.05 respectively). The combined effect of EB and P(4) was to stimulate the release of CCK and CGRP, and to increase the expressions of gastric CCK(A) and CGRP receptors. These results indicate that EB could inhibit gastric emptying by increasing CCK secretion and CCK(A) receptor expression in ovariectomized rats. P(4) could increase gut sensitivity by up-regulating the release of CGRP and the activity of CGRP receptor. It could be deduced from these observations that CCK(A) and CGRP receptor antagonists could be used for female patients who suffer from gastrointestinal dysfunction closely related with the menstrual cycle, such as distension, satiety, bloating and abdominal pain.
Animals ; Calcitonin Gene-Related Peptide ; blood ; Cholecystokinin ; blood ; Estradiol ; analogs & derivatives ; pharmacology ; physiology ; Female ; Gastric Emptying ; drug effects ; physiology ; Ovariectomy ; Progesterone ; pharmacology ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, Calcitonin Gene-Related Peptide ; metabolism ; Receptors, Cholecystokinin ; metabolism ; Stomach ; metabolism ; physiology

The effects of paraventricular nucleus (PVN) stimulation and vasopressin on gastric ischemia-reperfusion injury (GI-RI) were investigated in male SD rats of which the celiac artery was clamped for 30 min and reperfused for 1 h by removal of the clamp. The results were as follows. Both electrical and chemical stimulation of the PVN obviously attenuated the GI-RI. Bilateral electrolytic lesion of the nucleus tractus solitarius (NTS) or microinjection of AVP-V(1) receptor antagonist into the NTS could eliminate the protective effect of electrical stimulation of the PVN on GI-RI. Hypophysectomy did not influence the effect of electrical stimulation of the PVN. Both vagotomy and sympathectomy could increase the effect of stimulating PVN on GI-RI. Microinjection of arginine-vasopressin (AVP) into the PVN also attenuated the effect on GI-RI. These results suggest that the PVN and AVP participate in the regulation of GI-RI and play an important role in protection against GI-RI. This protective effect of PVN on GI-RI might be mediated by activation of AVP-ergic neurons in the PVN, which release AVP from the descending projection fibers and activate the AVP-V(1) receptors on the NTS neurons. The vagus and sympathetic nerves are involved in the efferent pathway exerting their effects on GI-RI. Hypophysis does not seem to be involved in the protective effect of PVN stimulation.
Afferent Pathways ; physiology ; Animals ; Electric Stimulation ; Male ; Paraventricular Hypothalamic Nucleus ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; physiopathology ; therapy ; Stimulation, Chemical ; Stomach ; blood supply ; Sympathetic Nervous System ; physiology ; Vagus Nerve ; physiology ; Vasopressins ; pharmacology

OBJECTIVETo study the expression and function of zinc ribbon gene ZNRD1 in drug-resistant cells of gastric cancer.

METHODSTwo tumor cell lines were used in this study: gastric cancer SGC7901 and its drug-resistant counterpart SGC7901/VCR stepwise-selected by vincristine. The expression of ZNRD1 in SGC7901 and SGC7901/VCR was detected by northern blot and semiquantitative RT-PCR. ZNRD1 antisense nucleic acid was transfected into SGC7901/VCR cells by lipofectamine. The expression of protein in SGC7901/VCR cells and the transfectants was detected by immunochemical method. Fluorescence activated cell scan (FACS) was applied to observe the cell cycle alteration. Growth curve and drug sensitization of cells for vincristine (VCR) and adriamycin (ADM) were analyzed by MTT assay.

RESULTSThe expression of ZNRD1 was higher in SGC7901/VCR than in SGC7901 cells. Immunochemical results showed that the expression level of ZNRD1 protein was lower in anti ZNRD1-SGC7901/VCR cells than in non-transfectants. The anti ZNRD1-SGC7901/VCR cells were gradually accumulated in G(1) phase, with a concomitant decrease of cell population in S phase. MTT assay showed that transfectant cell proliferation was lagged and more sensitive to VCR and ADM than non-transfectants.

CONCLUSIONZNRD1 gene displays high expression in VCR resistant gastric cancer cells. Expression of ZNRD1 protein is effectively blocked in anti ZNRD1-SGC7901/VCR cells by gene transfection. ZNRD1 antisense nucleic acid could reverse, to some degree, the MDR of human drug-resistant gastric cancer cell SGC7901/VCR.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA-Binding Proteins ; analysis ; genetics ; physiology ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; Humans ; Stomach Neoplasms ; chemistry ; drug therapy ; pathology ; Vincristine ; pharmacology

OBJECTIVETo study the effects of lysyl oxidase (LOX) on the migration and adhesion of the human gastric cancer cell line HGC-27 cells in vitro.

METHODSThe human gastric cancer cell line HGC-27 cells were cultured in vitro, and treated with different concentration of β-aminopropionitrile (BAPN). The ability of migration was assessed by wound-healing assay. The ability of adhesion was detected by homogenous and heterogeneous adhesion experiments.

RESULTSCompared that with 0 mmol/L BAPN, the ability of migration of the cells after treatment with 0.2 mmol/L BAPN was descended at 8, 24, 32 and 48 h; the number of cells with homogeneous adhesion was increased from (6.97 ± 0.07) × 10(3)/ml to (7.78 ± 0.11) × 10(3)/ml; and the number of cells with heterogeneous adhesion was decreased from (8.98 ± 0.15) × 10(3)/ml to (8.35 ± 0.10) × 10(3)/ml, both < 0.05. Compared with that of cells treated with 0 mmol/L and 0.2 mmol/L BAPN, the migration ability of cells after treatment with 0.3 mmol/L BAPN was descended at 8, 24, 32 and 48 h; the number of cells with homogeneous adhesion was raised to (8.02 ± 0.11) × 10(3)/ml and the number of cells with heterogeneous adhesion was down to (7.93 ± 0.07) × 10(3)/ml (P < 0.05).

CONCLUSIONLOX may promote the metastasis of cancer cells by enhancing invasion, increasing heterogeneous adhesion and decreasing homogeneous adhesion.

Aminopropionitrile ; administration & dosage ; pharmacology ; Cell Adhesion ; drug effects ; Cell Line, Tumor ; Cell Movement ; drug effects ; Dose-Response Relationship, Drug ; Humans ; Neoplasm Invasiveness ; Protein-Lysine 6-Oxidase ; antagonists & inhibitors ; metabolism ; physiology ; Stomach Neoplasms ; enzymology ; pathology