Synaptic processing in the gustatory brainstem

味觉脑干的突触处理

• 批准号: 7210585
• 负责人: Cheng-Shu Li
• 金额: $ 21.59万
• 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/7210585
• 关键词: Synaptic; processing; gustatory; brainstem

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）：抑制调节是孤束核（NST）味觉处理的一个重要方面。大量体内和体外研究表明，γ-氨基丁酸 (GABA) 是 NST 味觉处理中的抑制性神经递质。最近，甲硫脑啡肽对 NST 头端味觉反应神经元的影响已在体内模型中得到证实。在本申请中，研究了阿片类药物在味觉 NST 的味觉信息处理中充当抑制性神经肽的机制。这些实验涉及体外脑干切片制备，其中记录了从臂旁核（PbN）的味觉反应区域逆行标记的 NST 神经元的活动。这些实验检验了突触前和突触后机制都参与阿片类药物介导的味觉活动抑制的假设。 临床研究表明，单侧味觉神经损伤的患者通常报告味觉体验没有主观变化。这种“味觉恒定性”的机制被认为是集中发生的，最有可能发生在 NST 中。一些研究人员提出，鼓索 (CT) 神经味觉信息的丢失可以通过对第 IX 神经输入的抑制的释放来补偿。然而，从未研究过通过舌头另一侧的味觉输入进行补偿的可能性。本申请中的假设是NST神经元从舌头的同侧和对侧接收味觉信息，并且来自舌头对侧的上行通路涉及来自对侧NST的谷氨酸能投射。为了解决这些假设，PI建议使用全动物电生理学制剂，在其中可以从功能上研究外周味觉信息如何传递到对侧NST，以及体外切片制剂，其中可以更详细地研究参与这种双边通讯的突触机制。这些研究将为第一中枢味觉中继神经元参与调节和处理味觉信息的机制提供新的见解。