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Excitatory effect of norepinephrine on neurons in the inferior vestibular nucleus and the underlying receptor mechanism
Author(s) -
Peng ShiYu,
Zhuang QianXing,
Zhang YongXiao,
Zhang XiaoYang,
Wang JianJun,
Zhu JingNing
Publication year - 2016
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.23745
Subject(s) - neuroscience , excitatory postsynaptic potential , vestibular nuclei , vestibular system , locus coeruleus , brainstem , inhibitory postsynaptic potential , norepinephrine , medial vestibular nucleus , chemistry , nucleus , electrophysiology , biology , dopamine
The central noradrenergic system, originating mainly from the locus coeruleus in the brainstem, plays an important role in many physiological functions, including arousal and attention, learning and memory, anxiety, and nociception. However, little is known about the roles of norepinephrine (NE) in somatic motor control. Therefore, using extracellular recordings on rat brainstem slices and quantitative real‐time RT‐PCR, we investigate the effect and mechanisms of NE on neuronal activity in the inferior vestibular nucleus (IVN), the largest nucleus in the vestibular nuclear complex, which holds an important position in integration of information signals controlling body posture. Here, we report that NE elicits an excitatory response on IVN neurons in a concentration‐dependent manner. Activation of α 1 ‐ and β 2 ‐adrenergic receptors (ARs) induces an increase in firing rate of IVN neurons, whereas activation of α 2 ‐ARs evokes a decrease in firing rate of IVN neurons. Therefore, the excitation induced by NE on IVN neurons is a summation of the excitatory components mediated by coactivation of α 1 ‐ and β 2 ‐ARs and the inhibitory component induced by α 2 ‐ARs. Accordingly, α 1 ‐, α 2 ‐, and β 2 ‐AR mRNAs are expressed in the IVN. Although β 1 ‐AR mRNAs are also detected, they are not involved in the direct electrophysiological effect of NE on IVN neurons. All these results demonstrate that NE directly regulates the activity of IVN neurons via α 1 ‐, α 2 ‐, and β 2 ‐ARs and suggest that the central noradrenergic system may actively participate in IVN‐mediated vestibular reflexes and postural control. © 2016 Wiley Periodicals, Inc.