The type 2 ryanodine receptor of neurosecretory PC12 cells is activated by cyclic ADP-ribose. Role of the nitric oxide/cGMP pathway.
Of two neurosecretory PC12 cell clones that respond to NO donors and 8-bromo-cGMP with similar increases in cADP-ribose and that possess molecularly similar Ca2+ stores, only one (clone 16A) expresses the type 2 ryanodine receptor, whereas the other (clone 27) is devoid of ryanodine receptors. In PC12-16A cells, activation of the NO/cGMP pathway induced slow [Ca2+]i responses, sustained by release from Ca2+ stores. In contrast, PC12-27 cells were insensitive to NO donors. Likewise, in PC12-16A cells preincubated with NO donors, Ca2+ stores were partially depleted, as revealed by a test with thapsigargin, whereas those in clone 27 were unchanged. The NO-induced Ca2+ release was increased synergistically by caffeine, and the corresponding store depletion was magnified by ryanodine. The specificity for the NO/cGMP pathway was confirmed by the effects of two blockers of cGMP-dependent protein kinase I, while the role of cADP-ribose was demonstrated by the effects of its antagonist, 8-amino-cADP-ribose, administered to permeabilized cells. These results demonstrate in neurosecretory cells a ryanodine receptor activation pathway similar to that known in sea urchin oocytes. The signaling events described here could be of great physiological importance, especially in the nervous system.
Clementi
E
E
Department of Pharmacology, Faculty of Pharmacy, University of Reggio Calabria, 88021 Catanzaro, Italy.
Riccio
M
M
Sciorati
C
C
Nisticò
G
G
Meldolesi
J
J
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000378:metabolism; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D015415:Biomarkers; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D002227:Carbazoles; D036563:Cyclic ADP-Ribose; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000737:chemistry; D007211:Indoles; D015759:Ionomycin / Q000494:pharmacology; D009124:Muscle Proteins / Q000378:metabolism*; D009490:Neurosecretory Systems / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D016716:PC12 Cells; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel; D026423:S-Nitroso-N-Acetylpenicillamine; D015398:Signal Transduction; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D000470:Alkaloids; D015415:Biomarkers; D015220:Calcium Channels; D002227:Carbazoles; D007211:Indoles; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D013729:Terpenes; D036563:Cyclic ADP-Ribose; C073601:KT 5823; D009599:Nitroprusside; D000246:Adenosine Diphosphate Ribose; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D002110:Caffeine; D015759:Ionomycin; D019284:Thapsigargin; D026423:S-Nitroso-N-Acetylpenicillamine; D010396:Penicillamine; D006152:Cyclic GMP; D002118:Calcium