Upregulation of bradykinin B1‐receptor expression after myocardial infarction

To determine the influence of the myocardial infarction (MI) on bradykinin B1‐receptor (B1R) regulation, we studied its expression in the left ventricle (LV) after MI. Rats were submitted to a permanent occlusion of the left coronary artery. Six hours, 24 h and 6 days after MI or after sham operation, left ventricular pressure (LVP) and d P /d t max were measured. LV‐total RNA was extracted and B1R expression was analysed by a RNase‐protection assay (each group n =6). LVP and d P /d t max were impaired at all time points after MI. Basal B1R expression was not detectable in controls. Six hours after MI, the B1R expression was upregulated and reached a maximum 24 h after MI (4 fold vs 6 h). Six days post‐MI, B1R expression returned to levels found 6 h after MI. These data are the first demonstration for an induced myocardial B1R expression in an in vivo model of MI. British Journal of Pharmacology (2000) 129 , 1537–1538; doi: 10.1038/sj.bjp.0703239