Chronic Nicotine Effects on Receptor Subtypes

尼古丁对受体亚型的慢性影响

• 批准号: 7210709
• 负责人: DAVID C PERRY
• 金额: $ 33.05万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7210709
• 关键词: Acute; Affect; Agonist; Animals; Antibodies; Autoradiography; Behavioral; Binding; Biological Assay; Brain; Brain region; Cells; Cholinergic Receptors; Chronic; Classification; Drosophila acetylcholine receptor alpha-subunit; Drug Exposure; Employee Strikes; Equilibrium; Exposure to; Goals; Human; Immunoprecipitation; In Vitro; Infusion procedures; Injection of therapeutic agent; Knowledge; Lead; Length; Measurement; Measures; Mediating; Methods; Modeling; Neurobiology; Neurons; Neurotransmitters; Nicotine; Nicotine Dependence; Nicotinic Agonists; Numbers; Other Finding; Pattern; Perfusion; Pharmaceutical Preparations; Pharmacology; Proteins; Psychotropic Drugs; Pump; Quantitative Autoradiography; Rattus; Recovery; Reporting; Research Personnel; Resistance; Saline; Smoker; System; Techniques; Testing; Therapeutic Intervention; Time; Tobacco use; Up-Regulation; Week; desensitization; design; drug of abuse; epibatidine; follow-up; functional status; in vivo; neurotransmitter release; nicotine replacement; radioligand; receptor; receptor binding; receptor function; research study; response; smoking cessation; tobacco abuse; treatment effect

DESCRIPTION (provided by applicant): Prolonged exposure to nicotine causes profound alterations in nicotine receptors (nAChR), including upregulation and changes in functional status. While in vitro studies show clear differences in these responses among different nAChR subtypes, little is known about differential subtype responses after chronic nicotine exposure in vivo, such as occurs with use of tobacco products or nicotine replacement therapy. If the numbers and activity of some nAChR subtypes is altered more than other subtypes, this would change the pharmacological spectrum of activity and behavioral responses to nicotine; therefore knowledge of subtype-selective responses is essential for understanding nicotine neurobiology. The overarching goal of this proposal is to determine the consequences of chronic in vivo nicotine exposure on expression and function of nAChR subtypes, including alpha4-beta2, alpha-beta4 and alpha6/alpha3-beta2. Chronic drug exposure will be achieved by perfusion of rats with osmotic mini-pumps; it will be compared to acute exposure by injection. Aim 1 will employ a new method of quantitative autoradiography developed in our lab, using [1251] epibatidinewith subtype-selective competitors, that allows measurement of receptor subtypes in small regions, to assess effects of chronic nicotine exposure and recovery from such exposure. We predict that alpha4-beta2 receptors will be much more sensitive to upregulation, and recover more slowly. We will also test the effects of acute nicotine, to test whether effects seen are due to length of time of exposure. We will then use both homogenate binding and autoradiography with more selective radioligands to confirm any changes detected with [125l] epibatidine autoradiography. Aim 2 will use quantitative immunochemical techniques with subunit-selective antibodies to provide important confirmation and extension of any binding changes detected in Aim 1. Aims 3 and 4 will use two different methods to correlate binding changes to functional activity of nAChR subtypes; as above, we hypothesize that activity of alpha4-beta 2 receptors will be disproportionately affected by chronic nicotine. Functional changes caused by chronic (and acute) nicotine and recovery will be directly determined in multiple brain regions by measuring 86Rb efflux (Aim 3). Functional effects of treatments at the systems level will be assessed by measuring nicotinic-stimulated release of different neurotransmitters in selected regions (Aim 4). For these two aims, subtype selectivity will be obtained by the use of selective agonists and antagonists. The systematic application of these different methods to measure numbers and function of nAChR subtypes will allow us to develop a much more complete picture of the brain's response to chronic stimulation by this important drug of abuse.

描述（由申请人提供）： 长时间暴露于尼古丁会引起尼古丁受体（NACHR）的深刻改变，包括上调和功能状态的变化。尽管体外研究表明，不同NACHR亚型之间的这些反应明显差异，但对体内慢性尼古丁暴露后的差异亚型反应知之甚少，例如使用烟草产物或尼古丁替代疗法发生。如果某些NACHR亚型的数量和活性比其他亚型的变化更大，这将改变活性和行为反应对尼古丁的药理谱。因此，对亚型选择性反应的了解对于理解尼古丁神经生物学至关重要。该建议的总体目标是确定慢性体内尼古丁暴露对NACHR亚型表达和功能的后果，包括alpha4-beta2，alpha-beta4和alpha6/alpha6/alpha6/alpha3-beta2。慢性药物暴露将通过渗透迷你泵的大鼠灌注来实现；它将与注射急性暴露。 AIM 1将采用一种在我们的实验室中开发的定量自显影术的新方法，使用[1251] epibatidinewith Wwith亚型选择性竞争者，允许测量小区域中受体亚型的测量，以评估慢性尼古丁暴露和从这种暴露中恢复的影响。我们预测，α4-BETA2受体将对上调更加敏感，并且恢复更慢。我们还将测试急性尼古丁的作用，以测试所见效果是否是由于暴露时间的时间。然后，我们将使用具有更有选择性的放射性配体的匀浆结合和放射自显影术来确认[125L] Epibatidine放射自显影检测到的任何变化。 AIM 2将使用具有亚基选择性抗体的定量免疫化学技术来提供重要的确认并扩展AIM 1中检测到的任何结合变化。IAM3和4将使用两种不同的方法将结合变化与NACHR亚型的功能活性相关联；如上所述，我们假设α4-β2受体的活性会受到慢性尼古丁的影响不成比例的。由慢性（和急性）尼古丁引起的功能变化将通过测量86RB外排直接确定在多个大脑区域（AIM 3）。通过测量选定区域中不同神经递质的烟碱刺激释放来评估治疗在系统级别的功能效应（AIM 4）。对于这两个目的，使用选择性激动剂和拮抗剂将获得亚型选择性。这些不同的方法在测量NACHR亚型的数字和功能的系统应用将使我们能够通过这种重要的滥用药物对大脑对慢性刺激的反应进行更完整的了解。