02323nas a2200217   4500008004100000022001400041245007800055210006900133260001200202300001400214490000800228520164900236653003201885100002301917700002301940700002501963700002701988700002102015700002102036856004802057       2008                        eng d  a0022-307700aAn in vitro protocol for recording from spinal motoneurons of adult rats.0 ain vitro protocol for recording from spinal motoneurons of adult  c07/2008  a474–4810 v1003 aIn vitro slice preparations of CNS tissue are invaluable for studying neuronal function. However, up to now, slice protocols for adult mammal spinal motoneurons–the final common pathway for motor behaviors–have been available for only limited portions of the spinal cord. In most cases, these preparations have not been productive due to the poor viability of motoneurons in vitro. This report describes and validates a new slice protocol that for the first time provides reliable intracellular recordings from lumbar motoneurons of adult rats. The key features of this protocol are: preexposure to 100% oxygen; laminectomy prior to perfusion; anesthesia with ketamine/xylazine; embedding the spinal cord in agar prior to slicing; and, most important, brief incubation of spinal cord slices in a 30% solution of polyethylene glycol to promote resealing of the many motoneuron dendrites cut during sectioning. Together, these new features produce successful recordings in 76% of the experiments and an average action potential amplitude of 76 mV. Motoneuron properties measured in this new slice preparation (i.e., voltage and current thresholds for action potential initiation, input resistance, afterhyperpolarization size and duration, and onset and offset firing rates during current ramps) are comparable to those recorded in vivo. Given the mechanical stability and precise control over the extracellular environment afforded by an in vitro preparation, this new protocol can greatly facilitate electrophysiological and pharmacological study of these uniquely important neurons and other delicate neuronal populations in adult mammals.10aTissue and Organ Harvesting1 aCarp, Jonathan, S.1 aTennissen, Ann, M.1 aMongeluzi, Donna, L.1 aDudek, Christopher, J.1 aChen, Xiang Yang1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/18463177