Nitric oxide potentiates cAMP-gated cation current by intracellular acidification in feeding neurons of pleurobranchaea.
A pH-sensitive cAMP-gated cation current (I(Na,cAMP)) is widely distributed in neurons of the feeding motor networks of gastropods. In the sea slug Pleurobranchaea this current is potentiated by nitric oxide (NO), which itself is produced by many feeding neurons. The action of NO is not dependent on either cGMP or cAMP signaling pathways. However, we found that NO potentiation of I(Na,cAMP) in the serotonergic metacerebral cells could be blocked by intracellular injection of MOPS buffer (pH 7.2). In neurons injected with the pH indicator BCECF, NO induced rapid intracellular acidification to several tenths of a pH unit. Intracellular pH has not previously been identified as a specific target of NO, but in this system NO modulation of I(Na,cAMP) via pH(i) may be an important regulator of the excitability of the feeding motor network.
Potgieter
Kurt
K
Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA.
Hatcher
Nathan G
NG
Gillette
Rhanor
R
McCrohan
Catherine R
CR
D000818:Animals; D000242:Cyclic AMP / Q000494:pharmacology*; D004347:Drug Interactions; D045604:Extracellular Fluid / Q000187:drug effects / Q000502:physiology*; D005452:Fluoresceins; D017952:Ganglia, Invertebrate / Q000166:cytology; D006834:Hydrazines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D049853:Pleurobranchaea / Q000033:anatomy & histology / Q000502:physiology*
D005452:Fluoresceins; D006834:Hydrazines; D009025:Morpholines; D020030:Nitric Oxide Donors; C008550:morpholinopropane sulfonic acid; D009569:Nitric Oxide; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; C084012:1,1-diethyl-2-hydroxy-2-nitrosohydrazine; D000242:Cyclic AMP