- 5 ▁( S LC 1 A 3 , ▁S LC 1 A 2 , ▁S LC 1 A 1 , ▁, ▁). ▁Sub types ▁E A AT 1 - 2 ▁are ▁found ▁in ▁memb ran es ▁of ▁gli al ▁cells ▁( astro cy tes , ▁micro gl ia , ▁and ▁o lig od end ro cy tes ). ▁However , ▁low ▁levels ▁of ▁E A AT 2 ▁are ▁also ▁found ▁in ▁the ▁ax on - term inals ▁of ▁hi pp oc amp al ▁CA 3 ▁py ram idal ▁cells . ▁E A AT 2 ▁is ▁responsible ▁for ▁over ▁ 9 0 % ▁of ▁gl ut am ate ▁re upt ake ▁within ▁the ▁central ▁nerv ous ▁system ▁( C NS ). ▁The ▁E A AT 3 - 4 ▁sub types ▁are ▁exclus ively ▁neur onal , ▁and ▁are ▁expressed ▁in ▁ax on ▁terminal s , ▁cell ▁bodies , ▁and ▁d end rit es . ▁Finally , ▁E A AT 5 ▁is ▁only ▁found ▁in ▁the ▁ret ina ▁where ▁it ▁is ▁princip ally ▁local ized ▁to ▁phot ore cept ors ▁and ▁b ip olar ▁neur ons ▁in ▁the ▁ret ina . ▁ ▁When ▁gl ut am ate ▁is ▁taken ▁up ▁into ▁gli al ▁cells ▁by ▁the ▁E A AT s , ▁it ▁is ▁converted ▁to ▁gl ut am ine ▁and ▁subsequently ▁transport ed ▁back ▁into ▁the ▁pres yn apt ic ▁neur on , ▁converted ▁back ▁into ▁gl ut am ate , ▁and ▁taken ▁up ▁into ▁syn apt ic ▁ves icles ▁by ▁action ▁of ▁the