6.前庭神経核におけるモノアミンおよびペプチドの機能
2000 年 59 巻 1 号 p. 1-8
詳細
2000 年 59 巻 1 号 p. 1-8
In recent years, several monoamines and neuropeptides have been shown to act as neuromodulators in the vestibular system. This review focuses on the modulatory effects of monoamines including noradrenaline, dopamine, and serotonin, and peptides including somatostatin, opioid peptides, adrenocorticotropin, and tachykinins, on the neuronal activity of the central vestibular nuclei neurons, as well as the receptor subtypes involved in the effects induced by each of the monoamines or peptides. In vivo or in vitro electrophysiological studies have demonstrated that each of these monoamines or peptides inhibits, excites, or has both excitatory and inhibitory effects on the neuronal activity of vestibular nuclei neurons. However, there have been some discrepancies between the data obtained from electrophysiological studies and those by immunohistochemical or molecular biological works. In addition, although a few in vitro electrophysiological studies have tried to elucidate the mechanisms underlying the effects induced by monoamines, most of the ionic mechanisms as well as the site of action or the second messenger systems involved remain unidentified. Since recent works have suggested that some neurotransmitter-dependent conductances play roles in the central processing of vestibular inputs, and that the vestibular system can be used as a good model to elucidate some of the basic properties of the brain including learning, neural computation, network reconfiguration and post lesioned plasticity, the information on the detailed mechanisms underlying the modulatory effects induced by monoamines or peptides would be valuable not only for the understanding of the vestibular system but also for the treatment of the syndromes related to the vestibular system.
