TRH microinjection into DVC enhances motility of rabbits gallbladder via vagus nerve

Bi-directional regulation of acupuncture on extrahepatic biliary system: An approach in guinea pigs

Clinically, acupuncture affects the motility of the extrahepatic biliary tract, but the underlining mechanisms are still unknown. We applied manual acupuncture (MA) and electrical acupuncture (EA) separately at acupoints Tianshu (ST25), Qimen (LR14), Yanglingquan (GB34), and Yidan (CO11) in forty guinea pigs (4 groups) with or without atropinization under anesthesia while Sphincter of Oddi (SO) myoelectric activities and gallbladder pressure were monitored. In both MA and EA groups, stimulation at ST25 or LR14 significantly increased the frequency and amplitude of SO myoelectrical activities and simultaneously decreased the gallbladder pressure as compared to the pre-MA and pre-EA (P < 0.05). On the contrary, stimulation at GB34 or CO11 significantly decreased SO myoelectricity and increased the gallbladder pressure (P < 0.05). Pretreatment with atropine could abolish the effect of stimulation at acupoints ST25, GB34 and LR14 (P > 0.05), although significant myoelectricity increases were still inducible with MA or EA stimulation at CO11 (P < 0.05). In summary, acupuncture has bi-directional effects to gallbladder pressure and SO function, which probably due to autonomic reflex and somatovisceral interactions.

Liver injury is common among chronic abusers of ketamine

Abuse of ketamine leads to liver injury. We investigated the histopathologic and radiologic features of ketamine abusers with significant liver injury in a cross-sectional survey of 297 consecutive chronic abusers of ketamine with urinary tract dysfunction. Liver biopsy and magnetic resonance cholangiopancreatography were performed in patients with liver injury (concentrations of bilirubin, alkaline phosphatase, and/or alanine aminotransferase >2-fold the upper limit of normal). The prevalence of liver injury was 9.8% (all cases cholestatic). Bile duct injury was observed in all 7 patients assessed by liver biopsy. Two patients had bridging fibrosis despite their young age. Three of 6 patients who underwent magnetic resonance cholangiopancreatography examination were found to have prominent or dilated common bile ducts without obstructions or extrinsic compressions. Ketamine abuse therefore appears to lead to common bile duct dilatation, microscopic bile duct injury, and even significant liver fibrosis.

Oxytocin microinjected into dorsal motor nucleus of the vagus excites gallbladder motility via NMDA receptor-NO-cGMP pathway

Our recent study indicated that, in the dorsal motor nucleus of the vagus (DMV), the N-methyl-D-aspartic acid (NMDA) receptor-nitric oxide (NO)-cGMP pathway participated in the regulation of gallbladder motility in rabbits. Oxytocin (OT) is involved as a neurotransmitter in autonomic regulation. The aim of the present experiments is to investigate the effect of OT microinjected into DMV on the gallbladder motility and the involvement of NMDA receptor-NO-cGMP pathway. A frog bladder connected with transducer was inserted into the gallbladder to record the gallbladder pressure. Microinjection of OT (10-50 nmol/L, 100 nl) dose dependently increased the strength of gallbladder phasic contraction. The excitatory effect of OT (10 nmol/L, 100 nl) was completely abolished by atosiban (10 mmol/L, 100 nl), the specific OT receptor antagonist, but was not influenced by [deamino-Pen(1), O-Me-Tyr(2),Arg(8)]-vasopressin (10 mmol/L, 100 nl), the V(1) receptor antagonist. Pretreatment of ketamine (10 mmol/L, 100 nl), the NMDA receptor antagonist, suppressed the gallbladder motor response to OT; but pretreatment of 6-Cyaon-7-Nitroquinoxaline-2,3-(1H,4H)-Dione (CNQX; 10 mmol/L, 100 nl), the non-NMDA receptor antagonist, did not affect it. Pretreatment of L-NAME (10 mmol/L, 100 nl), the nitric oxide synthase (NOS) inhibitor, or methyl blue (10 mmol/L, 100 nl), the guanylyl cyclase inhibitor, inhibited the excitatory effect of OT on gallbladder motility. Hence, we deduced that the microinjection of OT into the DMV enhanced the gallbladder motility through binding specific OT receptors and activating the NMDA receptor-NO-cGMP pathway.

Effect of portal azygous disconnection on gallbladder motor function

AIM: To investigate and clarify the effect of vagus on gallbladder motility through a comparative study.

METHODS: Twenty-three hepatocirrhosis patients with portal hypertension were included in this study. In Hassab operation group, the anterior and posterior trunk of vagus were surgically excised (H, n = 18); In vena coronaria ventriculi embolization group, the vena coronaria ventriculi bole was ligated and injected TH adhesive (8 mL) after splenectomy (VCE, n = 5). Before operation and 10 d after operation, ^99mTc-labeled diethyl acetyl acid anilide iminodiacetic acid (^99mTc-EHIDA, 185 MBq) was administered intravenously to the patients, and then scintigraphic method was used to assess the motor function of gallbladder. The index including radiocounting 30 min after injected ^99mTc-EHIDA (GBRC 30min), emptying fraction (GBEF), emptying period (GBEP), emptying rate (GBER), latent period (GBLP), latent period radiocounting increment (GBLI) and latent period radiocounting increment rate (GBLR) were analyzed.

RESULTS: GBRC 30 min in H group was significantly lower after operation than that before operation (74.8 ± 66.9 vs 155.7 ± 72.9,P < 0.05); GBLP was very short in pre-operation, and GBLP prolonged significantly after operation (13.36 ± 5.92 vs 2.24 ± 1.48, P < 0.01); the gallbladder radiocounting increased gradually during GBLP; the GBLI and GBLP level were very low before operation, but the GBLI and GBLP increased significantly after operation (79.5 ± 56.3 vs 9.2 ± 11.7, 113.4 ± 49.5 vs 7.6 ± 10.8, P < 0.01); GBEP shortened significantly after operation (18.5 ± 6.3 vs 24.1 ± 6.4, P < 0.05); GBEF and GBER decreased obviously after operation (13.1 ± 5.4 vs 32.3 ± 16.3, 0.7 ± 0.3 vs 1.4 ± 0.8, P < 0.01). The preceding parameters in VCE group had no significant difference before and after operation (P > 0.05).

CONCLUSION: The gallbladder tension weakens obviously in interdigestive phase after the vagus is excised; the gallbladder contraction delays, and the motor function weakens obviously after meals.

Microinjection of glutamate into dorsal motor nucleus of the vagus excites gallbladder motility through NMDA receptor - nitric oxide - cGMP pathway

We have reported that both glutamate and nitric oxide (NO) participated in the regulation of gallbladder motility in dorsal motor nucleus of the vagus (DMV). The aim of this study is to investigate the type of receptor in DMV that mediates the excitatory effect of glutamate on gallbladder motility and the correlation between the glutamate and NO. A frog bladder connected with a force transducer was inserted into the gallbladder to record the change of gallbladder pressure. Glutamate (65 mmol L(-1), 100 nL) microinjected into DMV significantly increased the strength of gallbladder phasic contraction. This effect was abolished by ketamine (180 mmol L(-1), 100 nL), the specific N-methyl-d-aspartic acid (NMDA) receptor antagonist, but was not influenced by 6-cyaon-7-nitroquinoxaline-2,3-(1H,4H)-dione (CNQX) (180 mmol L(-1), 100 nL), the non-NMDA ionotropic receptor antagonist. N(G)-nitro-l-arginine-emthyl (l-NAME) (1 mol L(-1), 100 nL), the nitric oxide synthase (NOS) inhibitor, reversed the excitatory effect of glutamate on gallbladder motility. Microinjection of sodium nitroprusside (SNP), the NO donor, into DMV enhanced the gallbladder motility, and this effect was not modulated by ketamine. Microinjection of NMDA (5 mmol L(-1), 100 nL) increased the strength of gallbladder phasic contraction, and this effect was attenuated by methylene blue (100 mmol L(-1), 100 nL), the soluble guanylate cyclase inhibitor. These results suggest that glutamate regulate the gallbladder motility through the NMDA receptor - NO - cGMP pathway in DMV.

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Localization of neurokinin B receptor in mouse gastrointestinal tract

AIM: To observe the location of neurokinin receptor (NK3r) in the mouse gastrointestinal tract.

METHODS: The abdomens of 8 male Kunming mice were opened under anaesthesia with sodium pentobarbital. The exposed gut organs were kept moisture and temperature at the same time. Then the esophagus, jejulum, ileum, colon, etc were respectively cut and the segments from the stomach to the distal colon were opened along the mesenteric border. A circular 4 mm-6 mm enteric part(pieces of 1 cm² were to be prepared) and mucosa and submucosa were removed, then the longitudinal muscle layer was pulled off from the circular muscle layer under microphotograph. They were rinsed in 50 nmol·L^-1 potassium phosphate-buffered saline(PBS). Immunohistochemistry and immunoreactive fluorescence were used in the staining procedures.

RESULTS: There was not NK3r-Like(-Li) positive material on the smooth muscle cells of the esophagus, stomach, and intestines and other regions. The nerve cell bodies with immunoreactivity for NK3r were mainly distributed in the submucousal nerve plexus or myenteric nerve plexus of the gastrointestinal tract except for the esophagus, stomach and rectum. The reaction product was located on the surface of the nerve cell plasma. It was occasionally observed in the cell plasma endosomes, but was very weakly stained. Among the NK3-like positive neurons in the plexus,the morphological type in many neurons appeared like Dogiel II type cells. Some neuron cell bodies were big, having many profiles, some were long ones or having grading structure. Cell body diameter was about 10 μm-46 μm and 8 μm-42 μm in myenteric plexus and submucous plexus.

CONCLUSION: This study not only described the distribution of neurokinin B receptor in the mouse gut in detail, but also provided a morphological basis for deducing the functional identity of the NK3r-LI immunoreactivity neurons, suggesting the possibility that these neurons were closely related to gastrointestinal tract contraction and relaxing activity.