It is interesting to note that the majority of K2P channels show an up-regulation of expression in the retina between P10 and P14, at a similar time point to the functional maturation of visual pathways of the mouse retina7374. This observation may indicate that K2P channels perform important roles in vision. Glutamate is the key neurotransmitter by which bipolar cells transmit rod and cone derived signals to RGCs757677, and a previous study has described the presence of a glutamate sensitive background leak type K+ current in cultured mouse RGCs with properties of a TASK like current, most likely TASK-1 or TASK-378. Inhibition of this TASK-type current by the group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG) results in the depolarisation of retinal ganglion cells and increased levels of action potential firing, suggesting a significant role for TASK type channels in the regulation of RGC excitability by glutamate. Based on the results of our immunostaining data it would seem likely that TASK-1 channels, and not TASK-3 channels, may be responsible for the K+ leak current identified by these authors. However, in addition to TASK-1 (and TASK-3), several other K2P channels are known to be modulated by glutamate signalling pathways, including TREK-1 and TREK-2798081. It is therefore likely that K2P channels may mediate complex responses to glutamate within RGCs via multiple mechanisms.