ADP-ribosyl cyclase and cADPR hydrolase activity in cultures derived from rat cerebral cortex
| Astrocytes | AR cultures | AP cultures | |
|---|---|---|---|
| ADP-ribosyl cyclase [nmol cADPR synthesized/mg protein/hr (mean ± SEM)] | 0.84 ± 0.06 | 0.96 ± 0.18 | ND |
| cADPR hydrolase (1) (nmol cADPR degraded/mg protein/hr) | 167 | 111 | ND |
| cADPR hydrolase (2) (nmol ADPR accumulation/mg protein/hr) | 24 | 18 | ND |
For determination of ADP-ribosyl cyclase activity, cultures were incubated with 1 mm NAD in HBSS for 1 hr at 37°C in a shaking water bath, after which medium samples were bioassayed for cADPR activity (see text). cADPR hydrolase rates are given based both on cADPR loss and on ADPR gain in extracellular medium, based on data shown in Table 2. ND, Not detectable.