Anesthetic activation of TASK-3 tandem pore potassium channels: molecular mechanisms and behavioral effects

TASK-3串联孔钾通道的麻醉激活：分子机制和行为效应

• 批准号: 9900029
• 负责人: Joseph F Cotten
• 金额: $ 36.25万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9900029
• 关键词: 3-Dimensional; Amino Acids; Anesthesia procedures; Anesthetics; Animals; Behavioral; Binding; Biochemistry; Biological Assay; Brain; Cell Line; Codon Nucleotides; DNA sequencing; Development; Dose; Electroencephalogram; Electrophysiology (science); Essential Amino Acids; Fostering; General Anesthesia; Genes; Growth; Homology Modeling; Impaired cognition; Individual; Intravenous; Isoflurane; Knockout Mice; Lipid Bilayers; Mammalian Cell; Measures; Membrane; Mental Depression; Methods; Molecular; Molecular Biology; Mutate; Operative Surgical Procedures; Patients; Pharmaceutical Preparations; Pharmacology; Phenotype; Pichia; Population; Potassium; Potassium Channel; Probability; Property; Protein Structural Homology; Proteins; Rattus; Recovery; Reflex action; Regulation; Resistance; Rodent; Saccharomyces cerevisiae; Spinal Cord; Stimulus; Surveys; System; Terminator Codon; Testing; Time; United States; Work; Yeasts; base; cDNA Library; clinically relevant; desflurane; fitness; high throughput screening; in vivo; mutant; neuronal excitability; next generation; novel; pressure; response; sevoflurane; side effect; tribromoethanol; voltage clamp

Summary Over 40 million anesthetics are administered for surgical procedures in the United States every year. During these anesthetics, many patients receive halogenated anesthetic drugs such as isoflurane, sevoflurane, or desflurane. However, the pharmacologic mechanisms by which these drugs cause anesthesia are unclear. A detailed understanding of these mechanisms may foster development of safer, more selective anesthetics with fewer undesired side effects (e.g., cardiorespiratory depression and cognitive dysfunction), and drugs that facilitate recovery from general anesthesia. Using methods in yeast molecular biology, electrophysiology, and biochemistry as well as rodent studies, we will test the hypothesis that halogenated anesthetics cause anesthesia in part by direct binding and activation of TASK-3 potassium channels. TASK-3 is a membrane associated tandem pore potassium channel protein expressed in the brain and spinal cord that regulates neuronal excitability. TASK-3 potassium channel function is activated by isoflurane, sevoflurane, desflurane, and other halogenated anesthetics; and knockout mice lacking the TASK-3 gene require significantly higher doses of halogenated anesthetics for induction of loss of righting and to maintain immobility during a noxious stimulus. In Aim 1, we will use a yeast-based, high throughput screen of 4,693 TASK-3 missense mutants to identify TASK-3 amino acid residues critical for its function and for halogenated anesthetic activation. In Aim 2, we will purify functional wild-type and anesthetic-resistant mutant TASK-3 protein and measure their single channel function at baseline and following halogenated anesthetic treatment using the lipid bilayer voltage clamp method. Finally, in Aim 3 will administer potent and selective TASK-3 antagonist compounds to isoflurane anesthetized rats. We will quantify the TASK-3 antagonists' effects on the rat electroencephalogram (EEG) and on behavioral end points of anesthesia, loss of righting reflex and immobility during a noxious stimulus. The above studies will clarify the mechanism by which anesthetics interact with TASK-3 channels to cause activation. They will also reveal the contribution of TASK-3 to isoflurane anesthesia in a live, genetically unmodified animal.

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