Endogenous purinergic signaling is required for osmotic volume regulation of retinal glial cells (original) (raw)

2010, Journal of Neurochemistry

Neuronal activity is associated with rapid ion shifts between intra-and extracellular spaces (ECS) and changes in the cellular and ECS volumes. In the sensory retina, activation of neuronal ionotropic glutamate receptors has been shown to cause a net uptake of sodium chloride, resulting in a swelling of neuronal cell bodies and synapses, and a decrease in the ECS volume . During intense neuronal activity, retinal cells are surrounded by a hypoosmotic environment. Light-evoked changes in the ionic composition of the ECS fluid cause a decrease in osmolarity of the ECS fluid, because the decrease in sodium exceeds the increase in potassium by a factor of two, which is accompanied by a decrease in the chloride concentration ). An activity-dependent decrease in osmolarity of the ECS fluid was also observed in the brain . Retinal glial cells take up neuronderived osmolytes such as potassium and sodium-glutamate , which may elevate the intracellular space; IP 3 R2, inositol 1,4,5-triphosphate receptor type 2; MRS2179, N 6 -methyl-2¢-deoxyadenosine-3¢,5¢-bisphosphate; MRS2365, (N)-methanocarba-2MeSADP.