1990/05/31 |
Masuoka H, Ito M, Nakano T, Naka M, Tanaka T.
Biochem Biophys Res Commun. 1990 May 31;169(1):315-22.
Abstract
Ruthenium red inhibited Ca2(+)-dependent phosphodiesterase (Ca2(+)-PDE) selectively with an IC50 value of 15 microM. Increasing calmodulin concentration in the presence of both 100 microM and 4000 microM Ca2+ completely reversed the inhibition of Ca2(+)-PDE activity by ruthenium red. Ruthenium red-induced inhibition of Ca2(+)-PDE activity was also overcome by increasing the concentration of Ca2+ in the presence of both 200 ng and 2000 ng calmodulin, in sharp contrast to fluphenazine-induced inhibition of Ca2(+)-PDE. These results indicate that ruthenium red has distinct inhibitory mechanism which differs from that of calmodulin antagonists previously reported.