Calcium-dependent release of NO from intracellular S-nitrosothiols.
The paper describes a novel cellular mechanism for rapid calcium-dependent nitric oxide (NO) release. This release occurs due to NO liberation from S-nitrosothiols. We have analysed the changes of NO concentration in acutely isolated pancreatic acinar cells. Supramaximal acetylcholine (ACh) stimulation induced a Ca(2+)-dependent increase in the fluorescence in the majority of cells loaded with the NO probe DAF-FM via a patch pipette. The ACh-induced NO signals were insensitive to inhibitors of calmodulin and protein kinase C but were inhibited by calpain antagonists. The initial part of the NO signals induced by 10 muM ACh showed little sensitivity to inhibition of NO synthase (NOS); however, cell pretreatment with NO donors (increasing cellular S-nitrosothiol contents) substantially enhanced the initial component of NO responses. Pancreatic acinar cells were able to generate fast calcium-dependent NO responses when stimulated with physiological or supramaximal doses of secretagogues. Importantly, the source of this NO is the already available S-nitrosothiol store rather than de novo synthesis by NOS. A similar mechanism of NO release was found in dorsal root ganglia neurons.
Chvanov
Michael
M
The Physiological Laboratory, The University of Liverpool, Liverpool, UK. chvanov@liv.ac.uk
Gerasimenko
Oleg V
OV
Petersen
Ole H
OH
Tepikin
Alexei V
AV
D000109:Acetylcholine / Q000494:pharmacology; D000179:Acrylates / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D005452:Fluoresceins; D005456:Fluorescent Dyes; D005978:Glutathione / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology; D009569:Nitric Oxide / Q000096:biosynthesis*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010179:Pancreas / Q000166:cytology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D026403:S-Nitrosothiols / Q000378:metabolism*
C503301:4-amino-5-methylamino-2',7'-difluorofluorescein diacetate; D000179:Acrylates; D002147:Calmodulin; D005452:Fluoresceins; D005456:Fluorescent Dyes; D020030:Nitric Oxide Donors; C100442:PD 150606; D026403:S-Nitrosothiols; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C; D002154:Calpain; D005978:Glutathione; D000109:Acetylcholine; D002118:Calcium