Ionotropic Glutamate Receptors In Laternal Horn Of Spinal Cord Participating The Vestibular Blood Prssure Regulatin Mechanism Following The Acute Hypotension

The vestibular organ is composed of three semicircular canal, saccule and utricle, located in the deep of head on both sides of the temporal bone. The vestibular signal is passed to the vestibular nuclei by the eighth cranial nerves and affect blood pressure through a classic cardiovascular baroreceptor reflex. Many researches have showed that there are a lot of autonomic nerve nucleus in brainstem to regulate the cardiovascular function, which have the directly nerve fibers with vestibular nuclei. And our preliminary experiments have found that there is a pathway (Vestibular organ-MVN-NTS-RVLM) involved SNP-induced blood pressure regulation. MVN and RVLM can directly or indirectly through the spinal cord and adrenal medulla, participate in the vestibular blood pressure regulation. But the functional relationship between the spinal cord and adrenal medulla in this process is still unknown.Experimental AimTo explore the effects of glutamate receptors and weather the sympathetic preganglionic neurons of spinal cord grey matter side participate the regulation of SNP-induced actue hypotension.Experimental MethodsIn order to explore the vestibular blood pressure control in the process of the relationship between the spinal cord and the adrenal medulla and receptor mechanism. Research mainly through the following ways, the first one is surgery, eliminate rat aortic nerve and sinus nerve reflex, use the study of immunohistochemical and pharmacology experimental rats. First of all to inject the spinal cord segmental T4-T7 has gray side angle area into a certain amount of glutamate receptor blockers, observed in the rat of acuting hypotension caused by intravenous sodium nitrate tome, c-Fos within the adrenal medulla c-Fos protein expression. In order to explore the pathways, we observed after injection of glutamate receptor activator, by immunochemical method to observe the experimental rat adrenal medulla in activated c-Fos protein expression of positive neurons.Results1. The c-Fos protein expression in adrenal medulla decreased significantly and compared with the control group ACSF+SNP group has significant difference after injection of Glu inhibition (MK-801 or CNQX) into spinal cord grey matter side following acute hypotension induced by SNP 60 min(P<0.05, n=6).2.The c-Fos protein expression in adrenal medulla increased significantly and has significant difference compared with the control group ACSF group after injection of Glu excitation (NMDA or AMPA) into spinal cord grey matter side 60 min(.P<0.05, n=6).ConclusionsIonotropic glutamate NMDA and AMPA receptor involved in the vestibular blood pressure regulation by the spinal cord grey matter side.