▁/ ▁syn apt ic ▁ves icles , ▁and ▁then ▁released ▁with ▁other ▁ne uro trans mit ters ▁when ▁an ▁action ▁potential ▁provides ▁the ▁necessary ▁stim ulus ▁for ▁release . ▁▁ ▁The ▁concept ▁of ▁a ▁false ▁transmit ter ▁is ▁cred ited ▁to ▁Ir win ▁Kop in ▁of ▁the ▁National ▁Institute ▁of ▁Ne uro log ical ▁Dis orders ▁and ▁St roke ▁who ▁determined ▁that ▁the ▁drug ▁ty ram ine ▁increased ▁blood ▁pressure ▁by ▁being ▁loaded ▁and ▁then ▁released ▁from ▁secret ory ▁ves icles ▁of ▁the ▁ad ren al ▁chrom aff in ▁cells . ▁Ty ram ine ▁can ▁also ▁be ▁converted ▁into ▁oct op am ine ▁by ▁the ▁dop am ine - beta - h ydro x yl ase ▁( DB H ) ▁which ▁itself ▁acts ▁as ▁a ▁false ▁transmit ter ▁by ▁disp la cing ▁nor ad ren al ine ▁from ▁its ▁ves icle ▁but ▁not ▁activ ating ▁the ▁posts yn apt ic ▁alpha ▁ad ren ore ceptor . ▁ ▁There ▁is ▁growing ▁evidence ▁that ▁a ▁large ▁number ▁of ▁well ▁known ▁ex ogen ous ▁chemical s ▁work ▁as ▁substitute ▁ne uro trans mit ters , ▁though ▁the ▁distinction ▁between ▁the ▁classical ▁model ▁and ▁the ▁substitute ▁ne uro trans mit ter ▁model ▁only ▁becomes ▁apparent ▁with ▁ne uro trans mit ters ▁central ▁to ▁the ▁signal ing ▁in ▁the ▁conscious ▁brain , ▁like ▁dop am ine ▁and ▁ser ot on in ▁( as ▁mentioned ▁above ). ▁By ▁extension , ▁dru gs ▁that ▁affect ▁the ▁u pt ake ▁aff inity ▁of ▁ne uro trans mit ter ▁trans por ters