抄録
Anterior and posterior portion of the insular cortex is considered as a cortical gustatory and visceral sensory area, respectively. Many studies have indicated that both insular cortex and amygdala are important for the neural mechanisms of taste aversion learning. Anatomically, there is a reciprocal connection between the insular cortex and the amygdala. However, a few electrophysiological studies on these connections have been reported. It has been shown that GABAergic neurons have important roles in functions of the amygdala. In the present study, we investigated the changes in neuronal activity in the insular cortex after microinjection of GABA into the amygdala. Of the 9 rats, 5 were injected within or near the basolateral nucleus of the amygdala. In all 5 cases, spontaneous discharge rate of the insular cortex neurons was not affected after microinjection of GABA. In the remaining 4 rats, the injection sites were located outside of the amygdala. In these cases, spontaneous activity of the insular cortex neurons was unaffected after microinjection of GABA, except one case showing an excitatory response, which was injected into the piriform cortex. Previously, we reported that spontaneous activity of the insular cortex neurons was depressed after microinjection of glutamate into the amygdala. These results indicate that the effect of inhibitory chemical stimulation of the amygdala on the spontaneous activity of the insular cortex neurons is not simply reverse to that of excitatory chemical stimulation. [J Physiol Sci. 2007;57 Suppl:S164]
