Changes In Cardiovascular Function Caused By Insular Epilepsy Are Mediated By Habenular Body

Epilepsy is a common chronic disease in nervous system, which is often accompanied with complications in course .In the complications ,arrhythmia and cardiac arrest are the most harmful ,many patients'sudden cardiac death has no reason.In this situation,more and more scholars are beginning to research on brain-heart syndrome. Heart is related with central nervous system ,In normal condition, cortical center regulates cardiac activity by automatic nervous system in order to keep steady.Once neurologic function is abnormal ,it will break this steady state ,and cause arrhythmia and cardiac arrest .But the pathway in which neurologic disease causes heart damage is unclear, clinical observation and empirical study imply that insular lobe is cardiac autonomic nerve's cortical representation and in limbic system , the imbalance of cardiac autonomic nerve's activity caused by the damage of insular lobe and descending fiber may be the major mechanism of brain-originated heart injury,and both dorso-pathway mediated by habenular body and ventro-pathway mediated by hypothalamus are very critical.Recent study also concentrates on cardiovascular injury caused by insular lobe and neural biochemistry of nucleus which control cardiac activity. Whether insular epilepsy can cause definite changes in cardiovascular function is unclear,and which way such changes is mediated in is also unclear.So the effort to identify such mechanism and to give effective intervention to cerebrocardiac syndrome will have significant meaning. In order to verify the key roles that insular lobe and habenular body play in cardiovascular regulation and mediating, we have a research on the model of insular-epilepsy and Hb-destruction, discuss insular lobe and Hb's significantrole in cardiovascular regulation by recording the changes of blood pressure,heart rate and plasma norepinephrine in epilepsy group and destruction- epilepsy group rats.In doing this ,we will establish the foundation for brain-originated heart injury.Firstly, Wister rats are divided into A,B,C,D groups at random,each group has 8 rats. A is control group,B is epilepsy group ,C is pure destruction-group which is bred for one week after destruction in Hb, D is destruction-epilepsy group which is made a model of epilepsy again after destruction in Hb. Polyethylene catheter fulled with calparine is inserted into afferent extreme of rats'femoral artery to record blood pressure ; four-lead recording electrode are inserted into the proximal subcutaneous tissue of rats'four limbs to record electrocardiography.Secondly, inject kainic acid (KA) into A-group rats'insular lobe with the help of stereotaxic apparatus ,in order to make a model of insular epilepsy.Observe rats'ethologic changes , according to Racine-classification, make sure the seizure of epilepsy inⅣ-Ⅴgrade.Use BL-420E utility program to record blood pressure and electrocardiography in A-group and B-group.Thirdly, use direct current shock to destroy rats'bilateral Hb in C-group and D-group,feed such rats for one week in normal condition, record blood pressure and electrocardiography in C-group,then make a model of insular epilepsy again in D-group according to the procedures in 2.3,when the seizure inⅣ-Ⅴg rade takes place, record blood pressure and electrocardiography in D-group.Make a comparision and analysis among four groups.Fourthly,get left ventricle's blood samples in four groups ( blood samples in C and D group are collected in one hour after seizure), each sample is about 1.5-2ml, infuse samples into precooling tube fulled with calparine, centrifugalize and purify.Getthe supernatant liquid to measure Norepinephrine by spectrophotofluorometer. Finally, at the end of modeling , use microinjector to inject Pontamine-orchid into insular lobe to mark the position of injection. Also at the end of direct current shock ,at the destruction spot, use direct current of 200μA for 30s to make a mark.Get rats'brain after decapitation,and put them into formalin for one week ,then make coronal-slice in 40um to carry out a histologic identification.Results demonstrate: 1 the increase of blood pressure and heart rate in epilepsy-group is more significant than control group;in pure destruction-group,its rest blood pressure and heart rate in normal condition have no difference with control group; in destruction- epilepsy group which is compared with pure destruction-group, its blood pressure descends significantly but heart rate has no difference;but blood pressure and heart rate in epilepsy-group is much higher than destruction- epilepsy group.2 Norepinephrine in control group and pure destruction-group has no difference ;compared with control group, Norepinephrine in epilepsy-group increases significantly; and Norepinephrine in epilepsy-group is much higher than destruction-epilepsy group.on the basis of results,we can obtain such conclusions:1 changes of blood pressure and heart rate when the rats in right insular-epilepsy model have a seizure,imply that insular lobe has a close relationship with cardiovascular activity.2 From the comparision of blood pressure and heart rate between epilepsy-group and destruction-epilepsy group,we can infer that changes in cardiovascular activity caused by Insular epilepsy are mediated by Hb.Changes in Hb's activity also can change blood pressure and heart rate .3 pure destructionin bilateral Hb has no effect on rats'rest blood pressure in normal condition , but in stress condition such as seizure , rats'blood pressure descends significantly.It will imply that in stress condition, Hb has a critical role in blood pressure regulation.