CB1R independent effects of cannabinoids on synaptic physiology in the CNS.

描述(申请人提供)：这是一项基础科学提案，旨在使用体外电生理和光学技术来加深我们对在我的实验室中发现的一种极其不寻常的大麻依赖信号形式的理解。具体地说，我们观察到大麻素受体激动剂通过大麻素I型受体(CB1)受体非依赖机制增强动作电位非依赖于齿状回的GABA释放。尽管近年来关于内源性大麻素在中枢神经系统生理学中的具体作用带来了大量的新信息，但我们发现的大麻素受体激动剂的作用似乎在许多方面都是独一无二的。首先，它不依赖于CB1、CB2或香草素I型受体的激活，并且仍然存在于CB1-/-动物中。第二，它明显地调节动作电位非依赖性胞吐事件，而不改变动作电位依赖性事件；第三，它最终导致胞吐作用的促进(而不是抑制)。虽然我们的初步数据表明，在表征大麻素在中枢神经系统生理学中的新作用方面取得了重大进展，但关于这一新现象的许多基本问题仍然存在。因此，这项提案要求提供资金，通过执行两个具体目标继续我们在这一领域的调查。目的1将验证一种假说，即大麻素介导的动作电位非依赖性胞吐作用依赖于一个特定的配体受体与一个尚未确定的GPCR的相互作用。具体地说，我们假设G1S-&gt；AC-&gt；cAMP-&gt；PKA信号级联参与其中。目标2将验证这样的假设，即阿南达胺或其代谢物之一将是促进动作电位非依赖性释放的最有效的内源性可用配体，并且最好的激动剂将在生理相关的浓度范围内发挥良好的作用。总而言之，这些目的是为了提供数据，这些数据有可能清楚地确定我们的研究结果对大麻素领域的意义，并将直接促进对这一现象的长期和更大规模的调查。 与公共卫生相关：几乎所有已知的内源性大麻素的中枢效应都被认为是通过激活单一类型的受体--CB1大麻素受体--介导的。我们最近发现了一种非常新颖的大麻素介导的信号传递形式，它不依赖于CB1受体的激活，并且对中枢神经系统的生理有独特的影响。目前的提案旨在解决有关这一新信号系统的几个基本问题，我们希望这些问题最终将确立这一发现的总体意义(和潜力)。

DESCRIPTION (provided by applicant): This is a basic science proposal designed to use in vitro electrophysiological and optical techniques to further our understanding of an extremely unusual form of cannabinoid dependent signaling discovered in my lab. Specifically, we have observed that cannabinoid receptor agonists potentiate action potential independent release of GABA in the dentate gyrus through a cannabinoid type I (CB1) receptor independent mechanism. Although recent years have brought an enormous wealth of new information about the specific roles of endogenous cannabinoids in CNS physiology, the effect of cannabinoid receptor agonists that we have discovered appears to be unique in numerous respects. First, it does not depend on activation of CB1, CB2, or vanilloid type I receptors, and is still present in CB1-/- animals. Second, it clearly modulates action potential independent exocytotic events without altering action potential dependent events, and third, it ultimately results in the facilitation (rather than inhibition) of exocytosis. While our preliminary data represent significant progress towards characterizing a new role for cannabinoids in CNS physiology, many fundamental questions regarding this new phenomenon remain. Therefore this proposal requests funds to continue our investigation in this area through implementation of two Specific Aims. Aim 1 will test the hypothesis that cannabinoid mediated facilitation of action potential independent exocytosis depends on a specific ligand receptor interaction with an as yet unidentified GPCR. Specifically, we hypothesize that a G1s -> AC -> cAMP -> PKA signaling cascade is involved. Aim 2 will test the hypothesis that anandamide or one of its metabolites will be the most effective endogenously available ligand for facilitation of action potential independent release, and that the best agonists will work well within a physiologically relevant concentration range. Collectively, these Aims are designed to provide data that have the potential to clearly establish the significance of our findings for the cannabinoid field, and that will directly facilitate a longer term and larger scale investigation of the phenomenon. PUBLIC HEALTH RELEVANCE: Nearly all the known central effects of endogenous cannabinoids are thought to be mediated by activation of a single type of receptor, the CB1 cannabinoid receptor. We have recently discovered a highly novel form of cannabinoid mediated signaling that does not depend on CB1 receptor activation, and that has unique effects on CNS physiology. The current proposal is designed to address several fundamental questions about this new signaling system that we hope will ultimately establish the overall significance (and potential) of the finding.