emble ▁ion ▁channels . ▁These ▁trans por ters ▁play ▁the ▁important ▁role ▁of ▁reg ulating ▁concentr ations ▁of ▁gl ut am ate ▁in ▁the ▁ext rac ell ular ▁space ▁by ▁transport ing ▁it ▁along ▁with ▁other ▁ ions ▁across ▁cell ular ▁memb ran es . ▁ ▁After ▁gl ut am ate ▁is ▁released ▁as ▁the ▁result ▁of ▁an ▁action ▁potential , ▁gl ut am ate ▁trans por ters ▁quickly ▁remove ▁it ▁from ▁the ▁ext rac ell ular ▁space ▁to ▁keep ▁its ▁levels ▁low , ▁thereby ▁termin ating ▁the ▁syn apt ic ▁transmission . ▁ ▁Without ▁the ▁activity ▁of ▁gl ut am ate ▁trans por ters , ▁gl ut am ate ▁would ▁build ▁up ▁and ▁kill ▁cells ▁in ▁a ▁process ▁called ▁exc it ot ox icity , ▁in ▁which ▁excess ive ▁amounts ▁of ▁gl ut am ate ▁acts ▁as ▁a ▁to x in ▁to ▁neur ons ▁by ▁trigger ing ▁a ▁number ▁of ▁bio chem ical ▁cas c ades . ▁The ▁activity ▁of ▁gl ut am ate ▁trans por ters ▁also ▁allows ▁gl ut am ate ▁to ▁be ▁rec yc led ▁for ▁repeated ▁release . ▁ ▁Class es ▁ ▁There ▁are ▁two ▁general ▁classes ▁of ▁gl ut am ate ▁trans por ters , ▁those ▁that ▁are ▁dependent ▁on ▁an ▁electro chem ical ▁gradient ▁of ▁sod ium ▁ ions ▁( the ▁E A AT s ) ▁and ▁those ▁that ▁are ▁not ▁( V GL UT s ▁and ▁x CT ). ▁The ▁c yst ine - gl ut am ate ▁ant ip orter ▁( x CT )