▁bi ological ▁memb rane ▁prote ins ▁which ▁allow ▁the ▁pass ive ▁movement ▁of ▁ ions ▁( ion ▁channels ), ▁water ▁( aqu apor ins ) ▁or ▁other ▁sol utes ▁to ▁pass ively ▁pass ▁through ▁the ▁memb rane ▁down ▁their ▁electro chem ical ▁gradient . ▁They ▁are ▁studied ▁using ▁a ▁range ▁of ▁channel om ics ▁experimental ▁and ▁mathematical ▁techniques . ▁Ins ights ▁have ▁suggested ▁end oc ann ab ino ids ▁( e CB s ) ▁as ▁mole cules ▁that ▁can ▁reg ulate ▁the ▁opening ▁of ▁these ▁channels ▁during ▁diverse ▁conditions . ▁ ▁Properties ▁ ▁Hem ich annels ▁▁ ▁A ▁hem ich annel ▁is ▁a ▁memb rane ▁channel ▁made ▁up ▁of ▁six ▁sub un its . ▁A ▁hem ich annel ▁is ▁defined ▁as ▁one - half ▁of ▁a ▁gap ▁j unction ▁channel . ▁Hem ich annels ▁consist ▁of ▁conne x ins . ▁ ▁Pan nex in ▁ ▁Pan nex ins ▁are ▁involved ▁in ▁the ▁process ▁of ▁pur iner g ic ▁sign alling . ▁ ▁They ▁release ▁ad en os ine ▁tri ph osph ate ▁( AT P ), ▁which ▁activ ate ▁pur iner g ic ▁re cept ors . ▁ ▁On ▁the ▁other ▁hand , ▁pur iner g ic ▁re ceptor ▁activation ▁can ▁also ▁lead ▁to ▁the ▁opening ▁of ▁the ▁channel , ▁via ▁a ▁positive ▁feedback ▁loop . ▁ ▁In ▁addition , ▁P 2 Y ▁re cept ors ▁activ ate ▁in os it ol ▁tr is ph osph ate , ▁which ▁leads ▁to ▁a ▁trans ient ▁increase ▁in ▁int rac ell ular ▁calci um ,