Volatile Anesthetic Regulation of TASK Tandem Pore Potassium Channels

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This proposal describes a 5-year training program for the development of an independent investigator in volatile anesthetic mechanisms. The principal investigator is a faculty member in the Department of Anesthesia, Harvard Medical School, with a background in electrophysiology,who will acquire new knowledge and skills in neuroscience and pharmacology sufficient to lead his own independent research program. Work will be conducted in the Mallinckrodt Pharmacology Research Unit at Massachussets General Hospital which focuses on volatile anesthetic mechanisms. ; Our SPECIFIC AIMS wil test the novel hypothesis that volatile anesthetics potentiate TASK-3 function indirectly by inhibition of basal or agonst-mediated Galpha-q protein coupled receptor (GqPCR) activity. The TASK-3 tandem pore potassium channel is a volatile anesthetic-potentiated and pH- and hypoxia-inhibited ion channel. TASK-3 is widely expressed in the central nervous system and in peripheral tissue and has a role in chemosensing in a variety of cell types, including those involved in regulation of breathing. TASK-3 function is also inhibited by GqPCR activation. GqPCRs in the CNS regulate memory, wakefulness, and consciousness and peripherally are important regulators of smooth muscle tone. The function of many GqPCRs are inhibited by volatile anesthetics. To test our hypothesis we will use two-electrode voltage clamp of Xenopus oocytes or Ussing Chamber studies of Fischer Rat Thyroid cells heterologously expressing TASK-3 channels and ml or m3 GqPCRs and Galpha-q protein. We will also employ the excised patch-clamp method, and several molecular biology techniques including RNA interference and site-directed mutagenesis. LONG TERM GOALS: This project will clairfy the molecular mechanism by which volatile anesthetics potentiate TASK channels. RELEVANCE TO PUBLIC HEALTH: This work will help establish principles to guide development of safer anesthetic drugs that do not effect breathing and further elucidate the mechanism by which these drugs induce anesthesia. i