Endogenous purinergic signaling is required for osmotic volume regulation of retinal glial cells.

Intense neuronal activity in the sensory retina is associated with a volume increase of neuronal cells (Uckermann et al., J. Neurosci.

Involvement of A(1) adenosine receptors in osmotic volume regulation of retinal glial cells in mice.

Purpose: Osmotic swelling of Müller glial cells has been suggested to contribute to retinal edema. We determined the role of adenosine signaling in the inhibition of Müller cell swelling in the murine retina.

Methods: The size of Müller cell somata was recorded before and during perfusion of retinal sections and isolated Müller cells with a hypoosmolar solution.

Calcium responses mediated by type 2 IP3-receptors are required for osmotic volume regulation of retinal glial cells in mice.

Prevention of osmotic swelling of retinal glial (Müller) cells is required to avoid detrimental decreases in the extracellular space volume during intense neuronal activity. Here, we show that glial cells in slices of the wildtype mouse retina maintain the volume of their somata constant up to approximately 4 min of perfusion with a hypoosmolar solution. However, calcium chelation with BAPTA/AM induced a rapid swelling of glial cell bodies.