The 5-HT(4) receptor-induced depolarization in rat hippocampal neurons is mediated by cAMP but is independent of I(h)

Neurosci Lett. 2002 May 10;324(1):1-4. doi: 10.1016/s0304-3940(02)00113-1.

Abstract

Intracellular recordings were used to examine the mechanisms underlying the 5-hydroxytryptamine (5-HT)4 receptor-mediated depolarization seen in CA1 region pyramidal cells in in vitro hippocampal brain slices. This depolarization was mimicked and occluded by administration of the membrane permeable cyclic adenosine monophosphate (cAMP) analog 8-bromo-cAMP but was unaffected by blockade of protein kinase A (PKA). These results suggest that 5-HT4 receptors signal this depolarization through a cAMP-dependent but PKA-independent mechanism. In many cell types, 5-HT elicits a depolarization via cAMP by facilitating Ih, a hyperpolarization-activated cation current. In contrast, we find no evidence for the involvement of Ih in this response. Rather, this depolarization may involve a cyclic nucleotide gated channel.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 8-Bromo Cyclic Adenosine Monophosphate / pharmacology
  • Action Potentials / drug effects
  • Action Potentials / physiology*
  • Animals
  • Cations / metabolism
  • Cyclic AMP / analogs & derivatives
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Hippocampus / enzymology*
  • Ion Channels / antagonists & inhibitors
  • Ion Channels / metabolism*
  • Male
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / enzymology*
  • Organ Culture Techniques
  • Rats
  • Rats, Inbred Strains
  • Receptors, Serotonin / drug effects
  • Receptors, Serotonin / metabolism*
  • Receptors, Serotonin, 5-HT4
  • Serotonin Antagonists / pharmacology
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology

Substances

  • Cations
  • Enzyme Inhibitors
  • Ion Channels
  • Receptors, Serotonin
  • Serotonin Antagonists
  • Receptors, Serotonin, 5-HT4
  • 8-Bromo Cyclic Adenosine Monophosphate
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases