UPTAKE AND METABOLISM OF HISTAMINE BY THE RAT TAPEWORM HYMENOLEPIS-DIMINUTA - AN INVITRO STUDY

Authors
Citation
Ka. Yonge et Ra. Webb, UPTAKE AND METABOLISM OF HISTAMINE BY THE RAT TAPEWORM HYMENOLEPIS-DIMINUTA - AN INVITRO STUDY, Canadian journal of zoology, 70(1), 1992, pp. 43-50
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Zoology
Journal title
ISSN journal
0008-4301
Volume
70
Issue
1
Year of publication
1992
Pages
43 - 50
Database
ISI
SICI code
0008-4301(1992)70:1<43:UAMOHB>2.0.ZU;2-S
Abstract
The uptake of histamine by the rat tapeworm Hymenolepis diminuta was e xamined in intact worms and in worms denuded of tegument. Uptake was b y a sodium-independent mechanism and was not inhibited by compounds th at inhibit active transport of amines. The uptake of histamine was lin ear over all concentrations examined. including concentrations to whic h the worms are exposed in vivo. Q10 was consistent with uptake by sim ple diffusion. Histamine uptake was inhibited at pH 5.9 but not at hig her pH values. The only metabolite of histamine found was imidazole ac etic acid. Production of this metabolite was inhibited by heat treatme nt of the worms and by the presence of known diamine oxidase inhibitor s, suggesting the occurrence of diamine oxidase. This enzymatic activi ty was found in the tissues of the worm. In contrast, H. diminuta did not synthesize histamine from histidine. Collectively the data suggest that histamine in the tissues of H. diminuta is of exogenous origin. entering the tissues by diffusion, where it is metabolized by an endog enous diamine-like oxidase to imidazole acetic acid.