[Possible role of the AMPA/KA receptors in cultured Müller cells].

AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate)/KA (kainate) receptors have been demonstrated in cultured Müller cells in a study on cytosolic free calcium ions ([Ca2+]i). The action of these receptors may be expressed under pathological rather than physiological conditions. 1. Critical concentration in response to AMPA was determined in retinal neurons and Müller cells. At 0.05mM AMPA, in all neurons and in only a limited number of Müller cells (20%) cytosolic calcium transients occurred. 2. The level of lactate dehydrogenase (LDH) and the change in [Ca2+]i following AMPA administration were measured before and after exposure to 0.5mM KA. Neither morphological change nor leakage of LDH could be detected after 24 hours. When AMPA was administered, the responsive cell number was higher for KA-exposed cells than for control cells. Müller cells may be concluded to resist neurotoxic agents and may possibly be involved in the survival mechanism of retinal neurons.