Synaptic processing in the gustatory brainstem

味觉脑干的突触处理

• 批准号: 7027681
• 负责人: Cheng-Shu Li
• 金额: $ 22.24万
• 依托单位: SOUTHERN ILLINOIS UNIVERSITY CARBONDALE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7027681
• 关键词: afferent nerve; brain stem; chemoreceptors; chorda tympani; cranial nerves; electrodes; electrophysiology; endogenous opioid; hamsters; membrane potentials; neural information processing; neural transmission; neurons; neuropeptide receptor; neuropeptides; opioid receptor; potassium channel; single cell analysis; solitary tract nucleus; synapses; taste; taste buds; tissue /cell culture; tongue; voltage /patch clamp

DESCRIPTION (provided by applicant): Inhibitory modulation is an important aspect of taste processing in the nucleus of the solitary tract (NST). Numerous in vivo and in vitro studies have demonstrated gamma-aminobutyric acid (GABA) to be an inhibitory neurotransmitter in taste processing in the NST. Recently, the influence of met-enkaphalin on taste responsive neurons in the rostral NST has been demonstrated in an in vivo model. In the present application the mechanisms through which opioids act as inhibitory neuropeptides in taste information processing in the gustatory NST are investigated. These experiments involve an in vitro brainstem slice preparation in which the activity of NST neurons that have been retrogradely labeled from the taste responsive region of the parabrachial nuclei (PbN) is recorded. These experiments test the hypothesis that both presynaptic and postsynaptic mechanisms are involved in opioid-mediated inhibition of taste activity. Clinical studies show that patients with unilateral gustatory nerve damage often report no subjective change in taste experience. The mechanisms underlying this 'taste constancy' are thought to occur centrally, most likely in the NST. Several investigators have suggested that the loss of taste information from the chorda tympani (CT) nerve is compensated by a release of inhibition on IXth nerve input. However, the possibility of compensation by taste input from the other side of the tongue has never been investigated. The hypotheses in the present application are that NST neurons receive taste information from both the ipsilateral and contralateral sides of the tongue and that the ascending pathway from the contralateral side of the tongue involves glutamatergic projections from the contralateral NST. To address these hypotheses, the PI proposes to use both a whole-animal electrophysiological preparation, within which it is possible to investigate functionally how peripheral gustatory information is carried to the contralateral NST, and an in vitro slice preparation, in which the synaptic mechanisms involved in this bilateral communication can be studied in greater detail. These studies will provide new insights into the mechanisms by which neurons in the first central taste relay are involved in modulating and processing gustatory information.

描述（由申请人提供）：抑制性调节是味觉加工在孤立束核（NST）的一个重要方面。大量的体内和体外研究已经证明-氨基丁酸（GABA）是NST味觉加工中的一种抑制性神经递质。最近，在体内模型中证实了met-脑啡肽对吻侧NST味觉反应神经元的影响。在本研究中，研究了阿片在味觉NST中作为抑制性神经肽参与味觉信息加工的机制。这些实验包括体外脑干切片制备，其中记录了从臂旁核味觉反应区（PbN）逆行标记的NST神经元的活动。这些实验验证了突触前和突触后机制都参与阿片介导的味觉活动抑制的假设。