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Blocking of AMPA receptors in the central amygdaloid nucleus modulates the parabrachial nucleus taste responses in rats

Kang Yi, Yan Jianqun, Huang Tao

Department of Physiology,Key Laboratory of Environment and Genes Related to Diseases,Ministry of Education,Xi'an Jiaotong University School of Medicine.Xi'an 710061,Shaanxi

Abstract

Taste responses in the parabrachial nucleus (PBN) are significantly affected by stimulation or lesion of the central nucleus of the amygdala (CeA). To examine if the glutamate receptors in the CeA are involved in this modulation, the effects of microinjection of 6-cyano-7-nitro-quinoxaline-2, 3-dione (CNQX), an AMPA receptor antagonist, into the CeA on the activities of PBN taste neurons were observed by using extracellular recording technique. Responses of PBN taste neurons to taste stimuli were observed before and after CNQX administered to the CeA. In general, drug administration produced a time-dependent suppress of the responses in 30% PBN taste neurons, with the firing rates to HCl and QHCl were significantly lowered (P<0.05). According to the best-stimulus category, 40% NaCl-best (6/15), 30% HCl-best (3/10) and 20% QHCl-best (1/5) neurons decreased their responses to at least one basic taste stimulus after CNQX injection. In HCl- and QHCl-best neruons, the main responses were significantly inhibited after drug injections (P<0.01). The correlation coefficient of responses between the NaCl and the other three tastants decreased after drug administration to the CeA. These results suggest that AMPA receptors within the CeA may involve the descending modulation in the PBN taste neurons.

Key words: Parabrachial nucleus;Central nucleus of the amygdala;Taste;Microinjection;6-cyano-7-nitro-quinoxaline-2,3-dione

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Citing This Article：

Kang Yi, Yan Jianqun, Huang Tao. Blocking of AMPA receptors in the central amygdaloid nucleus modulates the parabrachial nucleus taste responses in rats. Acta Physiol Sin 2004; 56 (6): (in Chinese with English abstract).