Bradykinin activates ADP-ribosyl cyclase in neuroblastoma cells: Intracellular concentration decrease in NAD and increase in cyclic ADP-ribose

ADP-ribosyl cyclase activity in the crude membrane fraction of neuroblastoma × glioma NGPM1-27 hybrid cells was measured by monitoring [3H] cyclic ADP-ribose (cADPR) formation from [3H] NAD+. Bradykinin (BK) at 100 nM increased ADP-ribosyl cyclase activity by about 2.5-fold. Application of 300 nM BK to living NGPM1-27 cells decreased NAD+ to 78% of the prestimulation level at 30 s. In contrast, intracellular cADPR concentrations were increased by 2–3-fold during the period from 30 to 120 s after the same treatment. Our results suggest that cADPR is one of the second messengers downstream of B2 BK receptors.