Activity of histamine metabolizing and catabolizing enzymes during reperfusion of isolated, globally ischemic rat hearts.
Myocardial ischemia-reperfusion injury increases both tissue levels and release of histamine. To study the possible effects of ischemia-reperfusion on histamine metabolism tissue activities of histidine decarboxylase (HDC), histamine N-methyl transferase (HNMT) and diamine oxidase (DAO) were investigated in isolated rat hearts subjected to either 20 min global ischemia and 40 min reperfusion (n = 10) or control perfusion (n = 8). Histamine in the coronary effluent increased from 21 +/- 4 nmol/min (mean +/- SEM) before ischemia to 55 +/- 5 and 50 +/- 7 nmol/min after 4 and 10 min reperfusion (p < 0.004 and p < 0.004). Tissue HDC activity did not change during observation in any group. HNMT activity was unchanged in controls, but increased from 0.37 +/- 0.04 to 0.84 +/- 0.18 and 0.96 +/- 0.22 pmol methylhistamine/mg protein hour after 4 and 10 min reperfusion (p < 0.008 and p < 0.01). DAO decreased similarly in controls and ischemic-reperfused hearts during observation. In conclusion, the previously observed increase of tissue histamine during reperfusion cannot be explained by increased histamine synthesis or decreased histamine catabolism.
Valen
G
G
Department of Thoracic Surgery, Karolinska Hospital, Stockholm, Sweden.
Kaszaki
J
J
Szabo
I
I
Nagy
S
S
Vaage
J
J
D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D006632:Histamine / Q000378:metabolism*; D006637:Histamine N-Methyltransferase / Q000378:metabolism*; D006636:Histamine Release / Q000502:physiology; D006640:Histidine Decarboxylase / Q000378:metabolism*; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000503:physiopathology; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016277:Ventricular Function, Left / Q000502:physiology
D006632:Histamine; D006631:Amine Oxidase (Copper-Containing); D006637:Histamine N-Methyltransferase; D006640:Histidine Decarboxylase