passages.id: split_9_validation_1375_passage
passages.type: progene_text
passages.text: Analyzing 15 receptor subunits and five variants , we found all four alpha - amino - 3 - hydroxy - 5 - methyl - 4 - propionic acid ( AMPA ) and six NMDA receptor ( NR ) subunits as well as three of five kainate ( KA ) receptors ( GluR5 , GluR6 , and KA1 ) to be expressed in all nuclei .