Utilizing opioid receptor expression to identify the neurons and molecules responsible for opioid respiratory depression and basal breathing.

利用阿片受体表达来识别负责阿片类呼吸抑制和基础呼吸的神经元和分子。

基本信息

批准号：
10701824
负责人：
Kevin Yackle
金额：
$ 35.8万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-15 至 2027-06-30
项目状态：
未结题

项目摘要

Between 1999 and 2018 more than 446,000 people died from profoundly slow and shallow breathing after opioid overdose. This number grows at a faster rate each year and in 2019 there were nearly 50,000 overdose deaths. Opioids are perhaps the most effective analgesic, therefore, despite concern, they will persist as a staple therapy in medicine and within our society into the future. Thus, novel solutions to safely use opioids must be developed. But to discover these, we must first understand the key cellular and molecular mechanisms for opioid depression of breathing, known as opioid induced respiratory depression (OIRD). Recently we demonstrated that opioids depress breathing mostly through their action upon µ-opioid receptor (MOR) expressing neurons in the same site where the breathing rhythm is created, the preBötzinger Complex (preBötC). In this proposal, a central goal is to define the key preBötC neural type and MOR signaling pathway(s) that cause OIRD. Results from both aims will have direct clinical and therapeutic impact. Here, we hypothesize that opioids cause OIRD by blocking synaptic vesicle release from just 140 MOR+ excitatory preBötC neurons. Additionally, we expect that these same neurons, despite being less than 10% of preBötC, are specialized for creating the pace of breathing in general, analogous to the cardiac pacemaker cells. If so, these will be the first neurons identified with such an important purpose. This is the second central goal of the proposal. To test these three hypotheses, we have designed a sophisticated intersectional genetic approach to selectively delete MOR in adult mice from either excitatory or inhibitory preBötC neurons or nearby upper airway motor neurons to then compare if and how much OIRD changes. Next, we will use a sensitive in vitro system to uniformly test the necessity of each primary MOR signaling pathway in suppressing preBötC rhythmicity. And last, we will use an intersectional genetic approach to measure changes in breathing after acutely, ectopically silencing the preBötC MOR+ excitatory neurons. The identification of the cellular and molecular mechanisms of OIRD will establish a framework for future studies to develop novel pharmacological approaches to block or rescue it. Moreover, this proposal aims to determine if MOR+ excitatory neurons are pacemakers for breathing. If so, we will have identified, perhaps, some of the most vital neurons in the brain.

1999 年至 2018 年间，超过 446,000 人因使用阿片类药物后呼吸极慢且浅而死亡这个数字每年都以更快的速度增长，2019 年有近 50,000 人因服药过量死亡。阿片类药物可能是最有效的镇痛药，因此，尽管存在担忧，它们仍将作为主要疗法持续存在因此，必须开发安全使用阿片类药物的新解决方案。但要发现这些，我们必须首先了解阿片类药物抑郁症的关键细胞和分子机制呼吸抑制，称为阿片类药物引起的呼吸抑制（OIRD）。最近我们证明阿片类药物主要通过作用于 µ-阿片受体来抑制呼吸 (MOR) 在产生呼吸节律的同一位点表达神经元，即 preBötzinger 复合体 (preBötC) 在本提案中，一个中心目标是定义关键的 preBötC 神经类型和 MOR 信号通路。导致 OIRD 的结果将产生直接的临床和治疗影响。阿片类药物通过阻断 140 个 MOR+ 兴奋性前 BötC 神经元的突触小泡释放来引起 OIRD。此外，我们预计这些相同的神经元，尽管不到 preBötC 的 10%，但专门用于创造一般的呼吸节奏，类似于心脏起搏器细胞如果是这样的话，这些将是第一个。具有如此重要目的的神经元是该提案的第二个中心目标。三个假设，我们设计了一种复杂的交叉遗传方法来选择性删除 MOR 在成年小鼠中，从兴奋性或抑制性 preBötC 神经元或附近的上呼吸道运动神经元开始比较OIRD是否发生变化以及变化程度如何。接下来，我们将使用敏感的体外系统来统一测试OIRD。每个主要 MOR 信号通路在抑制 preBötC 节律性方面的必要性最后，我们将使用一个交叉遗传方法测量急性异位沉默 preBötC 后呼吸的变化 MOR+兴奋性神经元。 OIRD 细胞和分子机制的鉴定将为未来的研究建立框架此外，该提案旨在确定是否可以开发新的药理学方法来阻止或挽救它。 MOR+ 兴奋性神经元是呼吸的起搏器，如果是这样，我们也许已经确定了一些最重要的神经元。大脑中的重要神经元。