AUTONOMIC MUSCARINIC RECEPTOR SIGNALING MECHANISMS

自主毒蕈碱受体信号传导机制

基本信息

批准号：
2268852
负责人：
Fred J Ehlert
金额：
$ 21.76万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
1992
资助国家：
美国
起止时间：
1992-07-01 至 1996-06-30
项目状态：
已结题

项目摘要

The aims of this proposal are to seek out the pharmacological and neurophysiological functions of the M2 muscarinic receptor in the ileum, trachea and urinary bladder. It is known that the M3 muscarinic receptor elicits contraction in a variety of smooth muscles which respond to muscarinic agonists, yet the most abundant subtype of the muscarinic receptor is the M2, accounting for approximately 80% of the total density of muscarinic receptors in several smooth muscles. Surprisingly, the function of the M2 receptor in smooth muscle is essentially unknown. It is likely that the M2 receptor may cause a 'disinhibition of contraction' by preventing the relaxation elicited by other receptors which stimulate adenylate cyclase, like the beta-adrenergic receptor. Consequently, interactions between subtypes of the muscarinic receptor and other heterologous receptors will be investigated with respect to signaling mechanisms and contractility in smooth muscle. Part of the strategy for dissecting out the functional role of the M2 receptor in smooth muscle will involve the development of novel irreversible antagonists which inactivate M3 muscarinic receptors selectively. These agents should have widespread application as tools in a variety of neuropharmacological studies investigating the functional roles of subtypes of the muscarinic receptor. Moreover, the research described in this proposal could provide the basis for the development of more selective drugs for the treatment of paralytic ileus and glaucoma, and in determining how drugs used in psychiatry interfere with muscarinic cholinergic mechanisms. The specific experimental protocols are: 1) to characterize the muscarinic receptor binding properties of the irreversible muscarinic antagonist 4-DAMP mustard and to identify conditions where this antagonist blocks M3-stimulated phosphoinositide hydrolysis selectively without affecting M2-mediated inhibition of adenylate cyclase activity; 2) to develop new, more selective 4-DAMP mustard analogs; 3) to classify the subtypes of the muscarinic receptor mediating phosphoinositide hydrolysis and inhibition of adenylate cyclase activity in smooth muscle using subtype selective muscarinic antagonists; 4) to identify the subtypes of the muscarinic receptor present in smooth muscle using radioligand binding techniques; 5) to identify receptors which stimulate cyclic AMP accumulation in smooth muscle in a manner that is opposed by activation of the M2 muscarinic receptor; 6) to identify novel mechanisms of muscarinic receptor cross talk in smooth muscle; 7) to determine whether activation of M2 muscarinic receptors in smooth muscle prevents the relaxation mediated by the receptors identified in aim #2; and 8) to determine whether drugs of psychopharmacological interest interfere with muscarinic receptor signaling mechanisms in smooth muscle.

该提案的目的是寻找药理学和回肠中M2毒蕈碱受体的神经生理功能，气管和膀胱。众所周知，M3毒蕈碱受体引起各种光滑肌肉的收缩毒蕈碱激动剂，但是毒蕈碱的最丰富的亚型受体是M2，约占总密度的80％几种平滑肌肉中的毒蕈碱受体。令人惊讶的是， M2受体在平滑肌中的功能本质上是未知的。这是 M2受体可能会导致“抑制收缩” 防止其他受体引起的放松腺苷酸环化酶，例如β-肾上腺素能受体。最后，毒蕈碱受体和其他亚型之间的相互作用将研究有关信号的异源受体平滑肌的机制和收缩力。策略的一部分解剖M2受体在平滑肌中的功能作用将涉及新型不可逆拮抗剂的发展 M3毒蕈碱受体选择性地。这些代理应该广泛在各种神经药理研究中用作工具研究毒蕈碱受体亚型的功能作用。此外，本提案中描述的研究可以提供基础为了开发更多选择性药物以治疗麻痹回肠和青光眼，以及确定精神病学中使用的药物干扰毒蕈碱胆碱能机制。具体实验方案是：1）表征毒蕈碱受体不可逆的毒蕈碱拮抗剂4-DAMP的结合特性并确定该拮抗剂阻止M3刺激的情况磷酸肌醇水解有选择性地不影响M2介导的抑制腺苷酸环化酶活性； 2）开发新的，更有选择性 4-damp芥末类似物； 3）分类毒蕈碱的亚型受体介导磷酸肌醇水解和抑制腺苷酸的受体使用亚型选择性毒蕈碱在平滑肌中的环化酶活性对手； 4）确定存在的毒蕈碱受体的亚型在平滑肌中使用放射性结合技术； 5）识别刺激循环AMP在平滑肌中积累的受体 M2毒蕈碱受体的激活所反对的方式； 6）到识别毒蕈碱受体交叉聊天的新型机制肌肉; 7）确定M2毒蕈碱受体是否在平滑肌防止被鉴定的受体介导的松弛在AIM＃2中； 8）确定心理药物药物是否兴趣干扰光滑的毒蕈碱受体信号传导机制肌肉。