The Influence Of Autonomic Nerve Stimulation To Rapidatrial Pacemaker Dog Endothelial Function

Background: Study the neck autonomic nervous dry stimulus to rapid atrialpacemaker dog endothelial function related indicators, such as: Nitric Oxide(Nitric Oxide, NO), plasma Endothelin (Endothelin, ET), blood clotselement A2(ThromboxaneA2, TXA2) and forefront ring element(Prostacycline, PGI2) and calcitonin gene related Peptide (Calcitionin gene-related Peptide, CGRP) level of influence.Methods: Twenty four mongrel dogs were randomly divided into fourgroups: cervical vagosympathetic nerve stimulation (VNS) group, RAPgroup, VNS+RAP group and autonomic blockade+RAP group. Bilateralcervical vagosympathetic trunks was isolated in every dog, and the cranialends of the vagosympathetic nerves were ligated. A pair of teflon-coatedsilver wires was inserted into the cervical vagosympathetic trunks forstimulation. A bipolar pacing catheter was inserted in the right atrium by theway of the right femoral vein. In VNS group, vagosympathetic nerve wassuffering electric stimulation by the silver wires connected with vagusstimulator in order to decrease the baseline heart rate by50%. In RAP group,The rapid atrial pacing at600beats/min with a square waves of2×thresholdand1ms duration induced a acute AER. In VNS+RAP group, dogsunderwent both VNS and RAP. In autonomic blockade+RAP group, dogswere injected metoprolol and atropine parenteral solution, then received rapid atrial pacing. Blood samples were collected at0h,1h,2h,3h,4h,5h,6h after above operation. Enzyme linked immunosorbent assay (ELISA) waspreformed to measure the level of serum NO,PGI2,CGRP,ET and TXA2.Results: In VNS group, there were no significant differences in the serumlevels of NO,PGI2,CGRP,ET and TXA2throughout the6-hour stimulationperiod (p＞0.05). At RAP group, the NO,PGI2,CGRP,ET and TXA2levelschanged markedly after RAP (p＜0.05). In VNS+RAP group,theNO,PGI2,CGRP,ET and TXA2levels changed markedly afterstimulation.Compared with RAP Group, the differences were not significant.In autonomic blockade+RAP group, the NO,PGI2,CGRP,ET and TXA2levels changed markedly after stimulation. Compare with RAP Group, thedifferences were significant (p＜0.05).Conclusions:VNS has a slight influence in endothelial function.RAP couldresult in endothelium dysfunction.The influence of VNS+RAP was similarto RAP.Autonomic blockade+RAP could aggravate the endotheliumdysfunction caused by RAP.The results indicated that the vagus nerve couldhave a protective effect on endothelial function.