The Changes In Heart Rate Of Dexmedetomine On New Zealand Rabbits Which Cut Off The Autonomic Nervous

Background: By observing the influences,include heart rate,and Ach,of dexmedetomine on New Zealand rabbits which cut off the the Vagus nervous or the Sympathetic nervous,to investigate the channel of dexmedetomidine on decrease the heart rate.Improve the management quality of perioperative anesthesia.Method: 30 healthy male New Zealand rabbits randomly divided into 3 group,weight 2~2.5 kg: cut off Vagus group(V-group,n=10),cut off Sympathetic group(S-group,n=10),comparison group(C-group,n=10).After intravenous inject sodium pentobarbital,V-group cut off the bilateral Vagus nervous,S-group cut off the bilateral Sympathetic nervous,C-group separate bilateral autonomic nervous.Dexmedetomidine 3?g/kg was continous intravenous pumped,10 minute.Heart rate,arterial blood pressure,the level of acetylcholine and norepinephrine were measured at the following points: after anesthesia(T0),deal with autonomic nervous(T1),dexmetomidine infusion(T2).Use statistically analyze for the data.Result: 1.V-group and C-group HR: after the infusion of dexmedetomidine,the heart rate decreased in two groups and V group(194.10±21.44)showed significantly lower than C-group(219.20±15.56)(P<0.05),T0 and T1 showed no statistically significant,only the point T2(194.10±21.44)showed statistically significant when compare in group.MAP : compared with C-group,the MAP was higher at T1(93.23±5.89)and T2(63.56±11.23)points,in V-group,when cut off the Vagus nervous,the MAP increased and was statistically significant difference(P<0.05),after the infusion of dexmedetomidine,the MAP(63.56±11.23)was decreased but still higher than C-group(51.57±7.25).Ach: the two groups showed no significant difference at the point T0 and T1,compared to C-group,V-group was higher at T2 point(13.34±3.69)and was statistically significant difference(P<0.05).NE: compared with C-group(111.78±6.60),the levels of norepinephrine was higher at T1 point(139.57±30.39)(P<0.05),In V-group the levels of norepinephrine was higher at T1 point(139.57±30.39)and was statistically significant difference(P<0.05).2.S-group and C-group HR: compared to C-group(245.60±14.97),and(219.20±15.56),S-group was lower at T1(217.10±20.55)and T2(188.70±23.66)point(P<0.05),in S-group,the heart rate was significant difference lower as compared to baseline(234.90±23.39)level at T1(217.10±20.55)and T2(188.70±23.66)point.MAP:compared with C-group,the levels of MAP showed no significant difference,in S-group,the MAP decreased at T1(62.16±10.09),T2(53.63±10.73)points and showed statistically significant difference.Ach: the levels of acetylcholine was higher than C-group(10.02±2.18)at T2(12.55±2.54)point(P<0.05),S-group was higher at T2(12.55±2.54)point and was statistically significant difference(P<0.05).NE: the two groups showed no significant difference at the point T0 and T1,compared to C-group(103.17±6.46),S-group was higher at T2(119.65±16.83)point and was statistically significant difference(P<0.05),in S-group,the levels of norepinephrine showed no significant difference(P>0.05).Conclusion: After cut off the Vagus nervous or the Sympathetic nervous,dexmedetomidine can not only decrease heart rate,but also improve the content of acetylcholine.The probable mechanism is dexmedetomidine can increase the release of acetylcholine by some pathways except autonomic nervous.