Adenosine Promotes the Survival of Adult and Aged Pyramidal Neurons in Cultured Hippocampal Slices

grantor: University of TorontoTypically, pyramidal neurons in hippocampal slices from adult and aged rats die within the first 1-2 days 'in vitro'. We hypothesized that this cell death was due to the mechanical trauma and ischemia associated with the initial stages of culture, and that treatments leading to reduction of Ca++ influx would be neuroprotective. Adult hippocampal slices were prepared in HBSS and cultured on millipore membranes in culture media. Neuronal death was assessed using Propidium Iodide (PI). Mg++ (10mM) and low Ca++ (0 extracellular, no EGTA) significant reduced neuronal cell death for 1 week 'in vitro '. By the second week, however, neuronal cell death reached its maximum level. Adenosine (80-400uM) enhanced pyramidal neuronal survival for up to a month. The neuroprotective effects of adenosine were mimicked by 2-chloroadensoine and were blocked by theophylline (80uM). Adenosine also decreased the number of microglia present in the cultures. Taken together, these experiments show that the initial events are major determinants of the long-term survival of the adult and aged pyramidal neurons 'in vitro'; they also identify adenosine as a neuroprotective agent important for their survival in culture.M.Sc