TIME COURSE OF GLUTAMATE RECEPTOR EXPRESSION IN INDIVIDUAL OOCYTES OF XENOPUS-LAEVIS AFTER INJECTION OF RAT-BRAIN RNA

1. The receptor for the neurotransmitter glutamate was functionally expressed in oocytes of Xenopus laevis after microinjection of rat brain RNA. The functional differentiation of this receptor type was further analyzed. 2. The development of the sensitivity to the agonists showed a time course which was differential for the various ligands in individual oocytes. 3. Sensitivity appeared after one day for kainate (KA), after two days for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and quisqualate (QA), and after five days for N-methyl-D-aspartate (NMDA). 4. The KA response was markedly reduced by simultaneous application of AMPA. This was even found on the first day when an agonistic AMPA reaction was not detectable. 5. NMDA and non-NMDA receptors can clearly be differentiated by their delay of expression.