AUTONOMIC MUSCARINIC RECEPTOR SIGNALING MECHANISMS

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学功能， 气管和膀胱。 已知M3毒蕈碱受体 各种平滑肌的弹性收缩， 毒蕈碱激动剂，但最丰富的亚型的毒蕈碱 受体是M2，约占总密度的80 在几种平滑肌中的毒蕈碱受体。 令人惊讶的是， M2受体在平滑肌中的功能基本上是未知的。 是 M2受体可能通过以下方式引起“收缩解除抑制”： 防止由其他受体引起的松弛， 腺苷酸环化酶，就像β-肾上腺素能受体。 因此，委员会认为， 毒蕈碱受体亚型与其他受体亚型之间的相互作用 异源受体将被研究关于信号传导 机制和平滑肌的收缩性。 战略的一部分 剖析M2受体在平滑肌中的功能作用， 涉及开发新的不可逆拮抗剂， 选择性M3毒蕈碱受体。 这些代理商应该有广泛的 在各种神经药理学研究中用作工具 研究毒蕈碱受体亚型的功能作用。 此外，本提案中所述的研究可以为 用于开发更有选择性的药物来治疗麻痹症， 肠梗阻和青光眼，并确定如何使用药物在精神病学 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 不可逆毒蕈碱拮抗剂4-DAMP芥子气的结合特性 并确定这种拮抗剂阻断M3刺激的 磷酸肌醇选择性水解而不影响M2介导的 抑制腺苷酸环化酶活性; 2）开发新的、更有选择性的 4-DAMP芥末类似物; 3）对毒蕈碱的亚型进行分类， 受体介导磷酸肌醇水解和腺苷酸抑制 使用亚型选择性毒蕈碱的平滑肌环化酶活性 拮抗剂; 4）鉴定存在的毒蕈碱受体的亚型 在平滑肌中使用放射性配体结合技术; 5）鉴定 受体，刺激环磷酸腺苷的积累，在平滑肌中， 通过激活M2毒蕈碱受体对抗的方式; 6） 确定平滑中毒蕈碱受体串扰新机制 肌肉; 7）以确定是否激活M2毒蕈碱受体， 平滑肌阻止由识别的受体介导的松弛 在目标2和8中）确定精神药理学药物是否 兴趣干扰平滑肌中毒蕈碱受体信号传导机制 肌肉.

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.