Opioid-induced potentiation of the exercise pressor reflex via acid-sensing ion channels (ASIC3) in health and simulated peripheral artery disease

阿片类药物通过酸敏感离子通道 (ASIC3) 在健康和模拟外周动脉疾病中诱导运动升压反射增强

• 批准号: 10593184
• 负责人: Marc Peter Kaufman
• 金额: $ 61.35万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-20 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10593184
• 关键词: ASIC channel; Acidosis; Acids; Acute; Address; Affect; Afferent Neurons; Affinity; Analgesics; Applications Grants; Arteries; Atherosclerosis; Attention; Attenuated; Biophysics; Blood Pressure; Cardiac; Chemosensitization; Chest Pain; Chronic; Clinical; Contracts; Coronary Arteriosclerosis; Data; Disease model; Drops; Environment; Exercise; Fentanyl; Fibroblasts; Goals; Health; Heart Rate; Hyperalgesia; In Vitro; Inflammation; Inflammatory; Intermittent Claudication; Ions; Ischemia; Knock-out; L Cells; Lactic acid; Ligation; Mechanoreceptors; Mediating; Metabolic; Modeling; Muscle; Muscle Contraction; Muscle Fibers; Naloxone; Neurons; Opioid; Opioid Peptide; Opioid agonist; Oxycodone; Pain; Pain in lower limb; Patients; Perception; Perfusion; Peripheral arterial disease; Phase; Physiology; Play; Production; Protein Isoforms; Rattus; Receptor Activation; Reflex action; Reporting; Resistance; Rest; Role; Sensory; Site; Spinal Ganglia; Testing; Text; Thinness; Tissues; Toxin; Transfection; Walking; attenuation; blood pressure elevation; claudication; endogenous opioids; endomorphin 1; experimental study; femoral artery; in vivo; interstitial; ion channel blocker; limb ischemia; mu opioid receptors; novel; pharmacologic; prescription opioid; pressure; remifentanil; response; skeletal; ventilation; voltage

PROJECT SUMMARY Chronic ischemia in muscle (skeletal or cardiac) leads to accumulation of lactic acid and other inflammatory metabolites with subsequent drop in interstitial pH. The ensuing tissue acidosis plays a major role in triggering claudication (walking-induced pain) and chest pain. The high-affinity and selective mu opioid receptor (MOR) agonists, endomorphins, are also released under ischemic and inflammatory conditions. Acid-sensing ion channels (ASIC) are key players in the perception of pH changes associated with tissue acidosis, inflammation and pain. ASIC are expressed highly in sensory (i.e. dorsal root ganglion, DRG) and central neurons and are voltage-insensitive, depolarizing cationic channels. Endomorphin-1 (E-1) and -2 (E-2) are tetrapeptides known to activate MOR and exert analgesic effects. However, our recent findings indicate that E- 1 and E-2 significantly potentiated the acid-induced ASIC3 currents in transfected fibroblast L-cells and in acutely isolated DRG neurons independent of MOR activation. The potentiation by both opioids was significantly greater in DRG neurons isolated from rats with ligated femoral arteries (peripheral artery disease model). Importantly, our in vivo data demonstrated that E-2 significantly enhanced the lactic acid-induced increase in mean arterial pressure in rats. The E-2-mediated enhancement was significantly attenuated by the ASIC3 blocker, APETx2, but was insensitive to naloxone. Our long-term goal is to understand the mechanisms by which endomorphins and clinically employed opiates (oxycodone, fentanyl, remifentanil) modulate ASIC3 currents, the interacting site on the channel, and how they regulate the exercise pressor reflex (EPR) which is evoked by muscle contraction. Our overall hypothesis is that chronic muscle ischemia—accompanied by an acidified and inflamed environment, and enhanced ASIC3 expression— elevates endomorphin release, leading to enhanced ASIC3 currents. The overall effect is hyperexcitability of primary afferents that produces an exaggerated EPR. This hypothesis will be tested using complementary in vitro and in vivo approaches. We will determine the biophysical and pharmacological effects of endomorphins and prescription opiates on heterologously expressed ASIC3 in L-cells. We will identify ASIC3 channel residues that functionally negate the actions of E-1 and E-2, but leave the basic physiology of the channel intact. We also will compare the opioid agonist pharmacological profiles on ASIC channel currents in DRG neurons from rats with “freely perfused” or “ligated” femoral arteries. We will examine the effects of E-1, E-2 and prescription opiates on the EPR evoked in both wild-type and ASIC3 knockout rats in which the femoral arteries are “freely perfused” or “ligated”. Overall, these experiments will provide novel information about how opioid peptides potentiate ASIC currents under ischemic conditions, thereby enhancing pressor responses to exercise and possibly worsening pain associated with chronic use of prescription opiates (i.e., opioid-induced hyperalgesia).

项目摘要 肌肉中的慢性缺血（骨骼或心脏）导致漆酸和其他炎症的积累 代谢产物随后的间隙pH下降。随后的组织酸中毒在触发中起着重要作用 laurauration（行走引起的疼痛）和胸痛。高亲和力和选择性MU阿片受体（MOR） 激动剂，内啡肽也被释放在缺血性和炎症条件下。酸性离子 通道（ASIC）是感知与组织酸中毒相关的pH变化的关键参与者， 炎症和疼痛。 ASIC在感觉上高度表达（即背根神经节，DRG）和中央 神经元，是对电压不敏感的，分裂的阳离子通道。内啡肽1（E-1）和-2（E-2）为 四肽已知会激活MOR并发挥镇痛作用。但是，我们最近的发现表明e- 1和E-2在转染的成纤维细胞L细胞中以及在 急性分离的DRG神经元与MOR激活无关。两种阿片类药物的增强是 从结扎的股动脉（周围动脉疾病）的大鼠分离的DRG神经元中明显更大 模型）。重要的是，我们的体内数据表明，E-2显着增强了乳酸诱导的 大鼠平均动脉压的增加。 E-2介导的增强显着减弱了 ASIC3阻滞剂APETX2，但对纳洛酮不敏感。我们的长期目标是了解 内啡肽和临床采用操作的机制（羟考酮，芬太尼，瑞芬太尼） 调节ASIC3电流，通道上的相互作用位点，以及它们如何调节运动压力 肌肉收缩引起的反射（EPR）。我们的总体假设是慢性肌肉 缺血 - 由酸化和发炎的环境陪伴，并增强了ASIC3表达 - 提高内啡肽的释放，从而增强ASIC3电流。总体效果是过度兴奋 产生夸张的EPR的主要传入。该假设将使用完善 体外和体内方法。我们将确定内啡肽的生物物理和药物效应 以及在L细胞中异源表达ASIC3的处方鸦片。我们将确定ASIC3频道 残留在功能上否定E-1和E-2的作用但留下渠道的基本生理的残留物 完好无损的。我们还将比较DRG中ASIC通道电流的阿片类动力学药物概况 来自“自由灌注”或“连接”股动脉的大鼠的神经元。我们将检查E-1，E-2的影响 以及在野生型和ASIC3敲除大鼠中引起的EPR的处方鸦片 动脉被“自由灌注”或“连接”。总体而言，这些实验将提供有关如何 在缺血状态下，opioid petides促进了ASIC电流，从而增强了对压力的反应 运动和可能的遗憾与长期使用处方鸦片相关的疼痛（即，阿片类药物引起的 Hypergansia）。