, ▁pur ines ) ▁ne uro trans mit ters . ▁Gener ally , ▁expression ▁of ▁a ▁re ceptor ▁is ▁limited ▁to ▁a ▁subset ▁of ▁my enter ic ▁neur ons , ▁with ▁probably ▁the ▁only ▁exception ▁being ▁expression ▁of ▁nic ot in ic ▁ch ol iner g ic ▁re cept ors ▁on ▁all ▁my enter ic ▁neur ons . ▁One ▁re ceptor ▁that ▁has ▁been ▁target ed ▁for ▁th era pe ut ic ▁reasons ▁has ▁been ▁the ▁ 5 - h ydro xy try pt am ine ▁( 5 - HT 4 ) ▁re ceptor . ▁Activ ating ▁this ▁pre - syn apt ic ▁re ceptor ▁enh ances ▁ch ol iner g ic ▁ne uro trans mission ▁and ▁can ▁stim ulate ▁g astro int est inal ▁mot ility . ▁ ▁The ▁enter ic ▁nerv ous ▁system ▁exhib its ▁taste ▁re cept ors ▁similar ▁to ▁the ▁ones ▁in ▁the ▁tongue . ▁The ▁taste ▁re ceptor ▁T AS 1 R 3 ▁and ▁the ▁taste ▁G ▁protein ▁g ust du cin ▁are ▁two ▁of ▁the ▁most ▁common . ▁These ▁re cept ors ▁sense ▁" s weet ness " ▁on ▁the ▁tongue ▁and ▁sense ▁gl uc ose ▁in ▁the ▁enter ic ▁nerv ous ▁system . ▁These ▁re cept ors ▁help ▁reg ulate ▁the ▁secret ion ▁of ▁ins ul in ▁and ▁other ▁h orm ones ▁that ▁are ▁responsible ▁for ▁cont rolling ▁blood ▁sugar ▁levels . ▁ ▁C lin ical ▁significance ▁Hir sch spr ung ' s ▁disease ▁is ▁a ▁con gen ital ▁dis order ▁of ▁the ▁colon ▁in ▁which