A plant histaminase modulates cardiac anaphylactic response in guinea pig.
The effect of a copper amine oxidase (histaminase) purified from the pea seedling as free or immobilized enzyme on the response to specific antigen was studied in isolated hearts from actively sensitized guinea pigs. In vitro challenge with the specific antigen of hearts from actively sensitized animals evokes a positive inotropic and chronotropic effect, a coronary constriction, followed by dilation and an increase in the amount of histamine and nitrites, the oxidation product of nitric oxide, in the perfusates. In the presence of both forms of histaminases, the positive inotropic and chronotropic responses as well as the coronary constriction and the release of histamine were fully blocked. The amount of nitrites, appearing in the perfusates when anaphylaxis is elicited in the presence of both forms of histaminases, is significantly increased, as well as nitric oxide synthase activity and cyclic GMP content in cardiac tissue, while cardiac calcium overload was significantly prevented. These observations demonstrate that the decrease in the anaphylactic release of histamine and the subsequent abatement of the cardiac response to antigen can be accounted for by the inactivation by histaminase of the released histamine and by a stimulation of endogenous nitric oxide production.
A. Rossi Fanelli Department of Preclinical and Clinical Pharmacology, CNR Centre of Molecular Biology, Rome University La Sapienza, Piazzale A. Moro 5, 00185 Rome, Italy.
Emanuela
E
Masini
Alfredo
A
Vannacci
Cosimo
C
Marzocca
Pier Francesco
PF
Mannaioni
Olivia
O
Befani
Rodolfo
R
Federico
Alessandro
A
Toma
Bruno
B
Mondovì
D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism* / Q000494:pharmacology*; D000707:Anaphylaxis / Q000201:enzymology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003201:Computers; D006152:Cyclic GMP / Q000378:metabolism; D003720:Densitometry; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018532:Pisum sativum / Q000201:enzymology; D010936:Plant Extracts / Q000494:pharmacology; D013997:Time Factors
D010936:Plant Extracts; D009569:Nitric Oxide; D006632:Histamine; D019001:Nitric Oxide Synthase; D006631:Amine Oxidase (Copper-Containing); D006152:Cyclic GMP; D002118:Calcium