On-line detection of glutamate release from cultured chick retinospheroids.
A continuous fluorometric assay was adapted to measure the release of endogenous glutamate from cultured chick retinospheroids. The results obtained with this technique are compared with the release of [3H]D-aspartate from monolayer cultures of chick retina cells. It is shown that although excitatory amino acids may be released in a Ca(2+)-dependent manner, most of the neurotransmitter release from cultured retina cells occurs by reversal of the glutamate transporter. The presence of extracellular Ca2+ may actually inhibit glutamate release by the cells present in the retinospheroids, or the [3H]D-aspartate release by cells in monolayers, when veratridine is the depolarizing agent.
Duarte
C B
CB
Center for Neuroscience of Coimbra, Department of Zoology, University of Coimbra, Portugal. cbduarte@gemini.ci.uc.pt
Santos
P F
PF
Sánchez-Prieto
J
J
Carvalho
A P
AP
D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism / Q000493:pharmacokinetics; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D002122:Calcium Chloride / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D005470:Fluorometry; D005971:Glutamates / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012160:Retina / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
D018528:ATP-Binding Cassette Transporters; D027322:Amino Acid Transport System X-AG; D005971:Glutamates; D018377:Neurotransmitter Agents; D001224:Aspartic Acid; D011189:Potassium Chloride; D014701:Veratridine; D002122:Calcium Chloride; D002118:Calcium