Calcium signaling and neuronal vulnerability to ischemia in the striatum

Neurons express extremely different sensitivity to ischemic insults. The neuronal vulnerability is region-specific and the striatum is among the most susceptible areas to ischemic damage. Projecting GABAergic medium-sized neurons are very sensitive to energy metabolism impairment, whereas interneurons are selectively spared. However, the reasons for this differential vulnerability are largely unknown. Calcium ions (Ca²⁺) are important intracellular messengers enabling several physiological processes. However, excessive Ca²⁺ influx from the extracellular space or release from internal stores can elevate Ca²⁺ to levels that exceed the capacity of single neurons to appropriately buffer such overload. This capacity also appears to be a peculiar feature of single neuronal subtypes. This review will provide a brief survey of the ionic basis underlying the differential responses to in vitro ischemia of distinct striatal neuronal subtypes, mainly focusing on the role of Ca²⁺. The potential relevance of these findings in the development of therapeutic strategies for acute stroke will be discussed.