Increase in expression of P-2X1 receptors in the atria of patients suffering from dilated cardiomyopathy

P-2X1 receptors are ATP-sensitive ligand-gated cation-selective channels ab undant in smooth muscle tissues such as bladder and vas deferens. They have also been detected in the central and peripheral nervous system and in hea rt tissue. We have earlier reported distinct changes in the expression of t he PX1 subtype of P-2X receptors in hearts of patients suffering from dilat ed cardiomyopathy (DCM). The study was, however, based on Western blots fro m only five DCM samples and three control hearts. Moreover, the antibody wa s directed against a peptide derived from the sequence of rat P-2X1. In the present project we have examined larger groups of both DCM and control hea rts (n = 14 and 11, respectively). Furthermore, the antibody used in this p aper differs significantly from the one used in our previous report. The pr esent antibody was raised against an 18-residue peptide sequence (Lys 68-84 Val) derived from the human P-2X1 sequence. Most of the label in the Weste rn blots was concentrated over a triplet of bands migrating with an apparen t M-r of about 45 000. Quantitative densitometry indicated that this band w as more strongly expressed (by approximately 80%) in DCM hearts compared wi th the controls.