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Inhibitory responses of parabrachial neurons evoked by taste stimuli in rat

Lei Qi, Yan Jianqun, Shi Jinghong, Yang Xuejuan, Chen Ke

Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine.Xi'an 710061,Shaanxi

Abstract

In the present study, the responses of inhibitory gustatory neurons in the parabrachial nucleus （PBN） to four basic taste stimuli NaCl, HCl, quinine HCl （QHCl） and sucrose were examined using single-unit recording technique in anesthetized rats. A total of 18 inhibitory taste neurons in the PBN were obtained. Spontaneous firing rates of these inhibitory neurons were 0.2-5.5 Hz with mean firing rate of （2.15±0.31） Hz. Most of the neurons responded to more than one of the basic taste qualities. The inhibitory responses to taste occurred quickly and lasted 5-80 s in different PBN neurons. According to the responsive characteristics to the four basic taste stimuli, the neurons could be classified as NaCl-best （n=8）, HCl-best （n=3）, QHCl-best （n=3）, and sucrose-best （n=4）. The breadth of tuning of NaCl-best neurons was the highest （0.945）. Inhibitory responsive neurons had feeble discrimination among sapid stimuli or aversive stimuli. These results suggest that there exist inhibitory taste neurons in the PBN. These neurons may play some useful roles in precise transmission of taste information and the taste coding for hedonic and aversive tastes.

Key words: parabrachial nucleus;Taste;inhibitory response;Rat

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Citing This Article：

Lei Qi, Yan Jianqun, Shi Jinghong, Yang Xuejuan, Chen Ke. Inhibitory responses of parabrachial neurons evoked by taste stimuli in rat. Acta Physiol Sin 2007; 59 (3): 260-266 (in Chinese with English abstract).