Presynaptic cyclic nucleotide-gated ion channels modulate neurotransmission in the mammalian olfactory bulb.
Cyclic nucleotide-gated channels (CNGCs) on the dendritic cilia of olfactory receptor neurons (ORNs) are critical for sensory transduction in the olfactory system. Do CNGCs also play a role in the axons and/or nerve terminals of ORNs? We find that the cyclic nucleotides cAMP and cGMP can both facilitate and depress synaptic transmission between olfactory nerve fibers and their targets in olfactory bulb glomeruli. Cyclic nucleotides increase intracellular Ca(2+) in ORN terminals and enhance spontaneous transmitter release; at higher concentrations, cyclic nucleotides depress evoked transmission by altering olfactory nerve excitability. Cyclic nucleotides have no effect on transmission or nerve excitability, however, in mice lacking olfactory CNGCs. Taken together, our results identify a novel role for presynaptic CNGCs in modulating neurotransmission.
Murphy
Gabe J
GJ
Neuroscience Graduate Program and Department of Neuroscience, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA.
Isaacson
Jeffry S
JS
D000818:Animals; D002118:Calcium / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018755:GABA Agonists / Q000494:pharmacology; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D007473:Ion Channels / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009712:Nucleotides, Cyclic / Q000378:metabolism* / Q000494:pharmacology; D009830:Olfactory Bulb / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D004791:Enzyme Inhibitors; D018755:GABA Agonists; D007473:Ion Channels; D009712:Nucleotides, Cyclic; D005576:Colforsin; C016276:8-bromocyclic GMP; D006152:Cyclic GMP; D002118:Calcium