Activation of protein kinase A by nitric oxide in cultured dorsal root ganglion neurites of the rat, examined by a fluorescence probe, ARII.
To study the roles of nitric oxide (NO) in growth of nerve fibers, (+/-)-(E)-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexeneamine (NOR3), an NO-donor, was applied to cultured dorsal root ganglion (DRG) neurites from a micropipette. Ejection of a small volume of 1 mM NOR3 solution (not more than 1 pl/s) from a micropipette to terminal branches of neurites caused enlargement of the neurites, and often, elongation of their growth cones. This neurite enlargement was blocked by inhibitors for soluble guanylate cyclase. The neurite enlargement did not occur when protein kinase A (PKA) was inhibited. To prove that NOR3 activated PKA, we introduced a fluorescence peptide probe, ARII that reduces its fluorescence by activated PKA, to monitor PKA activity in DRG neurites. ARII fluorescence was reduced by NOR3, which was not observed when PKA was inhibited by its specific inhibitors. These indicated that PKA was indeed activated by NO. To examine whether the PKA activation is due to inhibition of phosphodiesterase III (PDE III) by cyclic GMP, we applied PDE III-specific inhibitors and found that the inhibitions activated PKA. Since PKA regulates various neuronal functions, our finding that NO activates PKA is important to understand roles of NO in nerve fibers.
Tsukada
Shingo
S
Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, 359-8513, Saitama, Japan.
Keino-Masu
Kazuko
K
Masu
Masayuki
M
Fukuda
Jun
J
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D004789:Enzyme Activation / Q000187:drug effects; D005456:Fluorescent Dyes; D005727:Ganglia, Spinal / Q000166:cytology*; D020439:Growth Cones / Q000187:drug effects / Q000201:enzymology; D006162:Guanylate Cyclase; D007546:Isoquinolines / Q000494:pharmacology; D020105:Milrinone / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009574:Nitro Compounds / Q000494:pharmacology; D010455:Peptides; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D044005:Tetrahydroisoquinolines
D005456:Fluorescent Dyes; D007546:Isoquinolines; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D010455:Peptides; D010726:Phosphodiesterase Inhibitors; D010975:Platelet Aggregation Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D044005:Tetrahydroisoquinolines; D009569:Nitric Oxide; C035964:trequinsin; C061872:FK 409; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP; D020105:Milrinone