2,3-butanedione monoxime blockade of Ca2+ currents in adult rat sympathetic neurons does not involve 'chemical phosphatase' activity.

Effects of the 'chemical phosphatase' 2,3-butanedione monoxide (BDM) on voltage-activated Ca2+ currents of adult rat superior cervical ganglion neurons were investigated using the whole-cell patch-clamp technique. BDM produced a rapid (< 10 s), reversible and dose-dependent (IC50 = 18.3 mM) inhibition of Ca2+ currents. The action of BDM was not prevented by 1 mM 8-(4-chlorophenylthio)-cAMP or 50 microM isoproterenol. H-7, a non-specific protein kinase inhibitor at 200 microM, did not prevent the rapid recovery from BDM-induced inhibition. Our results suggest that BDM inhibition of Ca2+ currents in rat sympathetic neurons does not require a 'chemical phosphatase' activity.