Gap junctional communication between glial cells is thought to play a role in K+ spatial buffering, in the propagation of inter-astrocytic Ca2+ waves, and in glial-neuronal signaling. In the present study, we characterize dye coupling between astrocytes, and between astrocytes and Muller cells, in the isolated rat retina. Whole-cell patch recordings were obtained from retinal astrocytes and Muller cells and the cells filled with Lucifer Yellow and neurobiotin. Spread of Lucifer Yellow to two to ten neighboring astrocytes occurred in 90% of the astrocyte recordings. After fixation and incubation of the retina with fluorescent conjugated streptavidin, neurobiotin was seen to label clusters of 13-88 astrocytes, as well as >100 Muller cells. In contrast, when Muller cells were filled with Lucifer Yellow and neurobiotin, both tracers were confined solely to the recorded Muller cell. The uncoupling agents octanol, halothane, and doxyl-stearic acid were tested for their ability to uncouple retinal glia in situ. All three agents eliminated the visible spread of Lucifer Yellow from the injected astrocyte and the spread of neurobiotin into Muller cells. However, only doxyl-stearic acid combined with octanol eliminated the spread of neurobiotin between astrocytes. These results demonstrate that astrocytes in the rat retina are coupled to each other and to Muller cells. The astrocyte-to-Muller cell coupling is asymmetric, allowing transfer of the tracer in the forward direction only. In addition, astrocyte-to-Muller cell coupling is more sensitive to the uncoupling agents tested than is astrocyte-to-astrocyte coupling.
|Original language||English (US)|
|Number of pages||13|
|State||Published - May 1 1997|
- Muller cell
- dye coupling
- gap junction
- intercellular coupling