Application of Tetrode Technology for Analysis of Changes in Neural Excitability of Medial Vestibular Nucleus by Acute Arterial Hypotension

Abstract

Objectives Excitability o medial vestibular nucleus (MVN) in the brainstem can be affected by changes in the arterial blood pressure. Several animal studies have demonstrated that acute hypotension results in the alteration of multiunit activities and expression of cFos protein in the MVN. In the field of extracellular electrophysiological recording, tetrode technology and spike sorting algorithms can easily identify single unit activity from multiunit activities in the brain. However, detailed properties of electrophysiological changes in single unit of the MVN during acute hypotension have been unknown. Methods Therefore, we applied tetrode techniques and electrophysiological characterization methods to know the effect of acute hypotension on single unit activities of the MVN of rats. Results Twoor3typesofunitcouldbeclassifiedaccordingtothemorphologyofspikes and firing properties of neurons. Acute hypotension elicited 4 types of changes in spontaneous firing of single unit in the MVN. Most of these neurons showed excitatory responses for about within 1 minute after the induction of acute hypotension and then returned to the baseline activity 10 minutes after the injection of sodium nitroprusside. There was also gradual increase in spontaneous firing in some units. In contrast small proportion of units showed rapid reduction of firing rate just after acute hypotension. Conclusions Therefore, application of tetrode technology and spike sorting algorithms is another method for the monitoring of electrical activity of vestibular nuclear during acute hypotension. Keywords: Medial vestibular nucleus; Acute arterial hypotension; Tetrode electrode; Spike sorting; Neuronal firing 중심 단어: ë‚´ì¸¡ì „ì •í•µ, 급성 ì €í˜ˆì••, í ŒíŠ¸ë¡œë“œ ì „ê·¹, 스파이크 분류, ì‹ ê²½ 흥분