Down-regulation and recovery of endothelin-1 binding and signaling in rat cardiomyocytes

Down-regulation and recovery of endothelin (ET) receptors and of ET-depende nt phosphoinositide-specific phospholipase C (PI-PLC) signaling was examine d in cultured cardiomyocytes from neonatal rats. Three hours treatment with 5 nM ET-1 decreased surface receptors to 30%, and transduction to 19%, of their respective time-zero values. After extensive washing and a 3 h recove ry period surface receptors returned to 74% of the time-zero value, with co ncomitant recovery of signal transduction to 75% of the time-zero value. Th e recovery of PI-PLC signaling in these cells is in contrast with a previou s report, but consistent with recovery of the receptor complement. (C) 2001 Academic Press.