fMet-Leu-Phe receptor expression by an interstitial cell in rabbit right atrium following left ventricular myocardial infarction.

Previous studies have shown that rabbit hearts subjected to in vivo left ventricular myocardial infarction and subsequent ex vivo perfusion respond to N-formylmethionyl-leucyl-phenylalanine (fMLP) with enhanced eicosanoid synthesis. This synthetic response occurs primarily in the right cardiac atrium, a site distant from the injury, and is not the result of increased enzymatic capacity for arachidonate metabolism. To further investigate the mechanism of this enhanced synthetic response, [3H]fMLP binding was characterized and binding sites were localized autoradiographically in intact tissue sections prepared from control hearts and hearts subjected to left ventricular myocardial infarction (1, 2, and 4 days postinfarction). Analysis of binding isotherms revealed a saturable high affinity (KD approximately 1 nM) fMLP binding site in the right cardiac atrium. After myocardial infarction specific binding in right atria (2 day) increased 12-fold (Bmax = 14.8 +/- 2.4 fmol/cm2) compared with normal controls (Bm...