When rats are exposed to room light from the dark, there is a transient inccrease of mRNA for the immediate-early genes c-fos and NGFI-A in the retina. Augmentation of c-fos and NGFI-A mRNA by light is apparently associated with activation of cholinergic nicotinic and muscarinic receptors as it can be suppressed by the nicotinic antagonist mecamylamine and the muscarinic antagonist atropine. Moreover, the light-induced increase of c-fos mRNA in retina appears to be associated with activation of glutamate receptors also as the noncompetitive inhibitor of N -methyl- d -aspartate receptors dizocilpine (MK-801) partially suppressed the increase of the c-fos message. Light-induced NGFI-A mRNA augmentation is apparently modulated by the same receptors. We were unable to detect light-induced changes of c-jun mRNA.
