TASK-3; TASK-3 immunoreactivity was predominantly observed for Müller cells (Fig. 3G), where expression of TASK-3 within Müller cells was confirmed by double labelling for the Mϋller cell marker glutamine synthetase62 (Fig. 3G–I). TASK-5; Due to the low levels of TASK-5 mRNA detected in the mouse retina we have not investigated the expression and distribution of TASK-5 protein.