Nitric oxide raises cytosolic concentrations of Ca2+ in cultured nodose ganglion neurons from rabbits.
The effects of donors of nitric oxide (NO), namely, S-nitroso-N-acetylpenicillamine-(SNAP) and E-methyl-2-E-hydroxyimino-5-nitro-6-methoxy-3-hexeneamide (NOR1), on cytosolic concentrations of Ca2+ ([Ca2+]i) were studied in cultured nodose ganglion neurons from newborn and young rabbits by loading with fura-2AM and microfluorometry. Application of SNAP (5 microM-1 mM) increased [Ca2+]i in 46% of neurons tested. The threshold dose of the response was 10 microM and the response increased in a dose-dependent fashion. The increase in [Ca2+]i at 50 microM averaged 74 +/- 8% above the control value. [Ca2+]i rose immediately after injection of SNAP and the plateau level was maintained in the presence of SNAP.NOR1, another donor of NO, increased [Ca2+]i with an average increase of 82 +/- 7% at 50 microM. Quantitation of NO gas in the solution of NOR1 by a redox chemiluminescence method revealed the constant release of 0.06 ppm NO from 5 ml of a 20 microM solution of NOR1. These data suggest that NO released from donors of NO induced an increase in [Ca2+]i in nodose ganglion neurons and, therefore, that NO might play a role as a transmitter or a modulator in autonomic primary sensory systems.
Sato
M
M
Department of Physiology, Akita University School of Medicine, Japan.
Kawatani
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003592:Cytophotometry; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D008163:Luminescent Measurements; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D009574:Nitro Compounds / Q000494:pharmacology; D009620:Nodose Ganglion / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011817:Rabbits; D026423:S-Nitroso-N-Acetylpenicillamine; D014665:Vasodilator Agents / Q000494:pharmacology
D005456:Fluorescent Dyes; D009574:Nitro Compounds; D014665:Vasodilator Agents; C101316:methyl-2-hydroxyimino-5-nitro-6-methoxy-3-hexeneamide; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D010396:Penicillamine; D002118:Calcium; D016257:Fura-2