The compounds are substituted thioalkyl , aminoalkyl and oxyalkyl guanidines which are {HEAD ~ inhibitors} of {TAIL ~ histamine activity} 
The compounds are substituted thioalkyl , aminoalkyl and oxyalkyl guanidines which are { HEAD ~ inhibitors } of { TAIL ~ histamine activity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL