Hanamori T, Kunitake T, Kato K, Kannan H
Department of Physiology, Miyazaki Medical College, Kiyotake, Miyazaki, Japan.
Brain Res. 1998 Feb 23;785(1):97-106. doi: 10.1016/s0006-8993(97)01392-9.
Extracellular unit responses to gustatory stimulation of the pharyngolaryngeal region, baroreceptor and chemoreceptor stimulation, and tail pinch were recorded from the insular cortex of anesthetized and paralyzed rats. Of the 32 neurons identified, 28 responded to at least one of the nine stimuli used in the present study. Of the 32 neurons, 11 showed an excitatory response to tail pinch, 13 showed an inhibitory response, and the remaining eight had no response. Of the 32 neurons, eight responded to baroreceptor stimulation by an intravenous (i.v.) injection of methoxamine hydrochloride (Mex), four were excitatory and four were inhibitory. Thirteen neurons were excited and six neurons were inhibited by an arterial chemoreceptor stimulation by an i.v. injection of sodium cyanide (NaCN). Twenty-two neurons were responsive to at least one of the gustatory stimuli (deionized water, 1.0 M NaCl, 30 mM HCl, 30 mM quinine HCl, and 1.0 M sucrose); five to 11 excitatory neurons and three to seven inhibitory neurons for each stimulus. A large number of the neurons (25/32) received converging inputs from more than one stimulus among the nine stimuli used in the present study. Most neurons (23/32) received converging inputs from different modalities (gustatory, visceral, and tail pinch). The neurons responded were located in the insular cortex between 2.0 mm anterior and 0.2 mm posterior to the anterior edge of the joining of the anterior commissure (AC); the mean location was 1.2 mm (n=28) anterior to the AC. This indicates that most of the neurons identified in the present study seem to be located in the region posterior to the taste area and anterior to the visceral area in the insular cortex. These results indicate that the insular cortex neurons distributing between the taste area and the visceral area receive convergent inputs from gustatory, baroreceptor, chemoreceptor, and nociceptive organs.
在麻醉并瘫痪的大鼠的岛叶皮质中记录了细胞外单位对咽喉区域味觉刺激、压力感受器和化学感受器刺激以及尾部夹捏的反应。在鉴定出的32个神经元中，28个对本研究中使用的九种刺激中的至少一种有反应。在这32个神经元中，11个对尾部夹捏表现出兴奋反应，13个表现出抑制反应，其余8个无反应。在这32个神经元中，8个通过静脉注射盐酸美索明（Mex）对压力感受器刺激有反应，4个为兴奋性，4个为抑制性。通过静脉注射氰化钠（NaCN）进行动脉化学感受器刺激时，13个神经元兴奋，6个神经元抑制。22个神经元对至少一种味觉刺激（去离子水、1.0 M氯化钠、30 mM盐酸、30 mM盐酸奎宁和1.0 M蔗糖）有反应；每种刺激有5至11个兴奋性神经元和3至7个抑制性神经元。在本研究使用的九种刺激中，大量神经元（25/32）接受来自不止一种刺激的汇聚输入。大多数神经元（23/32）接受来自不同模态（味觉、内脏和尾部夹捏）的汇聚输入。有反应的神经元位于前连合（AC）连接处前缘前方2.0 mm至后方0.2 mm之间的岛叶皮质中；平均位置在AC前方1.2 mm（n = 28）。这表明本研究中鉴定出的大多数神经元似乎位于岛叶皮质中味觉区域后方和内脏区域前方的区域。这些结果表明，分布在味觉区域和内脏区域之间的岛叶皮质神经元接受来自味觉、压力感受器、化学感受器和伤害感受器官的汇聚输入。
