Ca2+-dependent kainate excitotoxicity in the chick embryonic neural retina ex vivo.
The chick embryonic neural retina ex vivo has been singled out as a unique example of Cl(-)-dependent/Ca2+-independent excitotoxicity. However, after continuous incubation with 100 microM kainate, we have demonstrated the susceptibility of the chick retina to Ca2+-mediated damage, which becomes apparent after 12 h of exposure to the agonist in the absence of Cl-. Of the 20.8% lactate dehydrogenase released after 24 h incubation with kainate, some 11% is Cl(-)-dependent and the rest (9.8%) is presumably Ca2+-dependent. Upon omission of both Cl- and Ca2+, a 5% residual toxicity can still be detected after 24 h. This can be overcome by inclusion of EGTA in the incubation medium to neutralize Ca2+ released during incubation. A Ca2+-dependent toxicity mechanism is then operative in the embryonic chick retina ex vivo.
Burgos
J S
JS
Centro de Biologia Molecular (CSIC-UAM), Universidad Autónoma de Madrid, Spain.
Barat
A
A
Ramirez
G
G
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002642:Chick Embryo; D002712:Chlorides / Q000502:physiology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007608:Kainic Acid / Q000037:antagonists & inhibitors / Q000633:toxicity*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D012160:Retina / Q000187:drug effects* / Q000196:embryology
D002712:Chlorides; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; C056723:FG 9041; D016291:Dizocilpine Maleate; D007770:L-Lactate Dehydrogenase; D007608:Kainic Acid; D002118:Calcium