Changes in the synthesis and activity of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are associated with myocardial remodeling. Here we measured the expression and activity of MMPs and TIMPs, and tested the hypothesis that increased MMP activity plays a pro-apoptotic role in -AR-stimulated apoptosis of adult rat ventricular myocytes (ARVMs). -AR stimulation (isoproterenol, 24 h) increased mRNA levels of MMP-2 and TIMP-1 while decreasing TIMP-2 mRNA levels as analyzed by real time PCR. Western blot, immunocytochemical analysis, in-gel zymography, and MMP-2 activity assay confirmed -AR-stimulated increases in MMP-2 protein levels and activity. Inhibition of MMPs using GM6001 (a broad spectrum inhibitor of MMPs), SB3CT (inhibitor of MMP-2) and purified TIMP-2 inhibited -AR-stimulated apoptosis as determined by TUNEL staining. Treatment with active MMP-2 alone increased the number of apoptotic cells. This increase in MMP-2-mediated apoptosis was inhibited by GM6001 and SB3CT pretreatment. Co-immunoprecipitation studies indicated increased physical association of MMP-2 with 1 integrins following -AR stimulation. Inhibition of MMP-2 using SB3CT or stimulation of 1 integrin signaling using laminin inhibited the increased association of MMP-2 with 1 integrins. -AR stimulation increased poly-ADP-ribose-polymerase (PARP) cleavage, which was inhibited by inhibition of MMP-2. These data suggest that 1) -AR stimulation increases MMP-2 expression and activity, and inhibits TIMP-2 expression; 2) inhibition of MMPs, most likely MMP-2, inhibits -AR-stimulated apoptosis; 3) the apoptotic effects of MMP-2 may be mediated, atleast in part, via its interaction with 1 integrins and PARP cleavage.