| As the centrum of Parasympathetic preganglionic, nucleus ambiguus(NA), dorsal motornucleus of the vagus (DMV), nucleus of solitary tract (NTS) are acting on gastric motility.However, there are no unanimous standpoints about the effects of NA,DMV and NTS on thegastric motility by now. To clarify the effects of the three nucleus on gastric motility, ourresearch group have electrically stimulated the three nucleus respectively and found that allthe three nucleus inhibited gastric motility. These inhibiting results were due to excitement ofneuron body, or excitement of passed fibres? Whether excitement of neuron body orexcitement of passed fibres conduced to these inhibiting results was unclear. In this study, Weinjected L-Glutamate, a neuron body incitant, into NA,DMV and NTS to investigate theeffects of the three nucleus on gastric motility.We firstly investigated the effects of three kinds of concentrations of L-Glu which wereused as NA's stimulus on gastric motility after L-Glu injected into the right NA. Four groupsof experiments were performed. The concentration of 0.01mol/L, 0.1mol/L and 0.2mol/L wererespectively defined as low concentration, middle concentration and high concentration in thispaper, then the three different groups were respectively administered in the right NA. In thefourth group, Physiological saline was administered in the right NA. Then gastric motilitycurves, in which frequency, duration, amplitude, and index of motility were as indexes, wererecorded with intraluminal balloons and a two-lead physiological recorder. The resultsshowed that three kinds of concentrations of L-Glu administered in the right NA led tosignificant inhibition on gastric motility. Moreover, the inhibition had concentrationdependence and was more powerful with the increase of L-Glu concentration. However, therewas no obvious influence after Physiological saline was administered in the right NA. Itsuggested that the activity of NA inhibited gastric smooth muscles.According to discussed concentrations of L-Glu, we administered middle concentrationL-Glu in DMV and NTS, and observed the effects on gastric motility. Four groups ofexperiments were performed too. Firstly, L-Glu of middle concentration was administered inthe right DMV;Secondly, Physiological saline was administered in the right DMV;Thirdly,middle concentration L-Glu was administered in the right NTS;Fourthly, Physiologicalsaline was administered in the right NTS, then gastric motility curves were recorded in thesame method. The results showed that administering middle concentration L-Glu in DMVand NTS led to significant inhibition on gastric motility. It suggested that the activity ofDMV inhibited smooth muscles and NTS also participated in modulation of gastric functionin spite of a gut sensory nucleus.In addition, the results from stimulating the areas nearby NA,DMV and NTS, were alsocollected. The results showed that administering high concentration L-Glu in the rightintermediate reticular nucleus (IRT) led to significant excitation on gastric motility, Itindicated that there were neurons controlling excitation on gastric motility in this area. Butthere was no obvious change after middle concentration and high concentration L-Glu wererespectively administered in the right Parvicellular reticular nucleus (PCRT), It suggested thatneurons in this area did not control gastric motility significantly;Low concentration L-Gluadministered in the right Lateral reticular nucleus (LRT) led to significant inhibition on gastricmotility, It suggested that the activity of LRT inhibited smooth muscles.We compared the effects of administered middle concentration L-Glu in NA,DMV,NTSon gastric motility, The results showed that amplitude of gastric motility and index of gastricmotility presented an increasing current in NA,DMV and NTS. It suggested that administeredL-Glu in the right NTS had the largest inhibitory effect on gastric motility, DMV had thesecond largest effect, NA had the least effect on that.
|
PDF Full Text Request