OP ) ▁anti Ch Es ▁which ▁are ▁independent ▁of ▁their ▁en zym ic ▁block , ▁their ▁morph ogen etic ▁( ter at olog ic ) ▁effects ▁and ▁their ▁post n atal ▁behavior al ▁actions ▁resulting ▁from ▁their ▁pr en atal ▁application . ▁He ▁also ▁demonstrated ▁that ▁the ▁OP ▁anti Che ' s ▁damage ▁the ▁blood – bra in ▁bar rier . ▁These ▁studies ▁contributed ▁to ▁the ▁understanding ▁of ▁the ▁role ▁of ▁ch olin ester ases ▁as ▁morph og ens ▁and ▁" transport " ▁or ▁" sc aven ger " ▁en zym es ▁( Kar cz mar ▁et ▁al ., ▁ 1 9 5 1 ). ▁ ▁This ▁research ▁led ▁Kar cz mar ▁to ▁concept ual ize ▁on ▁the ▁pre - ne uro gen etic ▁appearance ▁of ▁components ▁of ▁the ▁ch ol iner g ic ▁system , ▁their ▁non - parallel ▁ont ogen esis ▁and ▁its ▁significance , ▁and ▁their ▁om ni - ex istent ▁ph y log en esis ▁which ▁is ▁independent ▁of ▁the ▁presence ▁of ▁inner v ation ▁or ▁mot ility . ▁ ▁Kar cz mar ▁and ▁Steve ▁Th es le ff ▁demonstrated ▁in ▁the ▁ 1 9 5 0 s ▁the ▁phenomen on ▁of ▁des ens it ization ▁( re ceptor ▁in activ ation ) ▁at ▁the ▁neur om yal ▁j unction , ▁and ▁Kar cz mar ▁described ▁the ▁reci pro cal ▁process , ▁sens it ization ▁which ▁is ▁indu cible ▁by ▁several ▁dru gs ▁such ▁as ▁ox am ides ▁and ▁Na F , ▁and ▁which , ▁today , ▁is ▁as