CAMP, Ca2+, pHi, and NO Regulate H-like Cation Channels That Underlie Feeding and Locomotion in the Predatory Sea Slug Pleurobranchaea californica

Daniel J. Green, Rong Chi Huang, Leland Sudlow, Nathan Hatcher, Kurt Potgieter, Catherine McCrohan, Colin Lee, Elena V. Romanova, Jonathan V. Sweedler, Martha L.U. Gillette, Rhanor Gillette

Research output: Contribution to journalReview article

Abstract

A systems approach to regulation of neuronal excitation in the mollusc Pleurobranchaea has described novel interactions of cyclic AMP-gated cation current (INa,cAMP), Ca2+, pHi, and NO. INa,cAMP appears in many neurons of feeding and locomotor neuronal networks. It is likely one of the family of hyperpolarization-activated, cyclic-nucleotide-gated currents (h-current) of vertebrate and invertebrate pacemaker networks. There are two isoforms. Ca2+ regulates both voltage dependence and depolarization-sensitive inactivation in both isoforms. The Type 1 INa,cAMP of the feeding network is enhanced by intracellular acidification. A direct dependence of INa,cAMP on cAMP allows the current to be used as a reporter on cAMP concentrations in the cell, and from there to the intrinsic activities of the synthetic adenyl cyclase and the degradative phosphodiesterase. Type 2 INa,cAMP of the locomotor system is activated by serotonergic inputs, while Type 1 of the feeding network is thought to be regulated peptidergically. NO synthase activity is high in the CNS, where it differs from standard neuronal NO synthase in not being Ca2+ sensitive. NO acidifies pHi, potentiating Type 1, and may act to open proton channels. A cGMP pathway does not mediate NO effects as in other systems. Rather, nitrosylation likely mediates its actions. An integrated model of the action of cAMP, Ca2+, pHi, and NO in the feeding network postulates that NO regulates proton conductance to cause neuronal excitation in the cell body on the one hand, and relief of activity-induced hyperacidification in fine dendritic processes on the other.

Original languageEnglish (US)
Pages (from-to)1986-1993
Number of pages8
JournalACS Chemical Neuroscience
Volume9
Issue number8
DOIs
StatePublished - Aug 15 2018

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Keywords

  • Command neuron
  • h-current
  • intracellular pH
  • nitric oxide
  • peptide

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Cognitive Neuroscience
  • Cell Biology

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