Rat hippocampal neurons express genes for both rod retinal and olfactory cyclic nucleotide-gated channels: novel targets for cAMP/cGMP function.
Cyclic nucleotide-gated (CNG) channels are Ca(2+)-permeable, nonspecific cation channels that can be activated through direct interaction with cAMP and/or cGMP. Recent electrophysiological evidence for these channels in cultured hippocampal neurons prompted us to investigate the expression of CNG channel genes in hippocampus. PCR amplification detected the expression of transcripts for subunit 1 of both the rod photoreceptor (RCNGC1) and the olfactory receptor cell (OCNGC1) subtype of CNG channel in adult rat hippocampus. In situ hybridization detected expression of both channel subtypes in most principal neurons, including pyramidal cells of the CA1 through CA3 regions and granule cells of the dentate gyrus. From the hybridization patterns, we conclude that the two genes are colocalized in individual neurons. Comparison of the patterns of expression of type 1 cGMP-dependent protein kinase and the CNG channels suggests that hippocampal neurons can respond to changes in cGMP levels with both rapid changes in CNG channel activity and slower changes induced by phosphorylation. Future models of hippocampal function should include CNG channels and their effects on both electrical responses and intracellular Ca2+ levels.
Kingston
P A
PA
Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06520, USA.
Zufall
F
F
Barnstable
C J
CJ
D000818:Animals; D000242:Cyclic AMP / Q000502:physiology*; D006152:Cyclic GMP / Q000502:physiology*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000096:biosynthesis; D054815:Cyclic Nucleotide-Gated Cation Channels; D018891:Dentate Gyrus / Q000166:cytology / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D017403:In Situ Hybridization; D015640:Ion Channel Gating; D007473:Ion Channels / Q000096:biosynthesis* / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009833:Olfactory Pathways / Q000502:physiology; D016133:Polymerase Chain Reaction; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism; D015347:RNA Probes; D051381:Rats; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology; D014158:Transcription, Genetic
D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels; D015347:RNA Probes; D000242:Cyclic AMP; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP