The possibility of passive transport of histamine through biological membranes

The possibility of transport of free and heparin-bound histamine along the concentration gradient through bimolecular lipid membranes (BLM) and the influence of various factors on it was studied. It was shown that histamine is capable of diffusing through BLM in the form of a singly charged cation. In contrast to histamine, neither heparin nor the histamine-heparin complex (HsHC) penetrates through BLM. It was established that the action of histamine-liberating factors -- increasing the ionic strength to 0.15 and the addition of trypsin to the solution -- on HsHC leads to the appearance of transport of histamine through the BLM as a result of an increase in the concentration of free histamine in solution.