The Type 2 Ryanodine Receptor of Neurosecretory PC12 Cells Is Activated by Cyclic ADP-ribose

doi:10.1074/jbc.271.30.17739

The Type 2 Ryanodine Receptor of Neurosecretory PC12 Cells Is Activated by Cyclic ADP-ribose

ROLE OF THE NITRIC OXIDE/cGMP PATHWAY*

From the ^‡ Department of Pharmacology, Faculty of Pharmacy, University of Reggio Calabria, 88021 Catanzaro, Italy, the
^∥ Department of Biology, Mondino Neurobiology Centre, University of Roma “Tor Vergata,” 00133 Roma, Italy, and the
^§ Consiglio Nazionale delle Ricerche, Molecular and Cellular Pharmacology Centre and the Department of Pharmacology, B. Ceccarelli Centre, University of Milano, Dipartimento di biotecnologie, San Raffaele Scientific Institute, 20132 Milano, Italy

^¶ To whom correspondence should be addressed:
Dip. Farmacologia, DIBIT, Scientific Institute San Raffaele, Via Olgettina 58, 20132 Milano, Italy.
Tel.: 39-2-26432770; Fax: 39-2-26434813; E-mail: clemene{at}dibit.hsr.it

Abstract

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.

Footnotes

↵* This work was supported in part by grants from the Italian Association of Cancer Research, the Human Frontier Science Program, and the Target Project Applicazioni Cliniche della Ricerca Oncologica of the Italian Consiglio Nazionale delle Ricerche. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

RyR

ryanodine receptor

IP₃

inositol 1,4,5-trisphosphate

SERCA

sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase

SNAP

S-nitroso-N-acetylpenicillamine

(R_p)-8-Br-cGMP-S

(R_p)-8-bromoguanosine 3′:5′-monophosphorothioate

SNP

sodium nitroprusside

Ab

antibody

KRH

Krebs-Ringer Hepes

MOPS

3-(N-morpholino)propanesulfonic acid.
↵² A. Galione, personal communication.
- Received February 26, 1996.
- Revision received April 8, 1996.