Nitric oxide selectively enhances cAMP levels and electrical coupling between identified RPaD2/VD1 neurons in the CNS of Lymnaea stagnalis (L.).
The isolated CNS of the freshwater mollusc Lymnaea stagnalis was used as a model to study the role of cAMP in NO-mediated mechanisms. The NO donor, DEA/NO (10(-5)-10(-3) M) increased cAMP concentrations in the cerebral, pedal, pleural, parietal and visceral ganglia. In contrast, in the buccal ganglia the same doses of DEA/NO decreased the level of cAMP production. The NOS inhibitor, L-NNA (10(-4) M) increased cAMP concentrations in all areas of the CNS. L-arginine (1 mM), a metabolic precursor of NO, mimicked the action of the NO-donor. The coefficient of electrical coupling between two viscero-parietal peptidergic neurons (VD1/RPaD2) was enhanced by both DEA/NO (10(-4) M) and 8-Br-cAMP (10(-4) M) whereas 8-Br-cGMP (2x10(-4) M) reduced the coupling. We suggest that cAMP-dependent mechanisms are involved in neuronal NO signaling in this simpler nervous system.
Sidorov
A V
AV
Department of Physiology, Byelorussian State University, Minsk, Republic of Belarus.
Kazakevich
V B
VB
Moroz
L L
LL
D000818:Animals; D002490:Central Nervous System / Q000166:cytology*; D000242:Cyclic AMP / Q000096:biosynthesis / Q000378:metabolism*; D008195:Lymnaea / Q000502:physiology*; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*
D009569:Nitric Oxide; D000242:Cyclic AMP