title: Spontaneous gating of olfactory cyclic-nucleotide-gated channels.
abstract: In vertebrates, cilia on the olfactory receptor neurons have a high density of cyclic-nucleotide-gated (CNG) channels. During transduction of odorous stimuli, cyclic AMP is formed. cAMP gates the CNG channels and this initiates the neuronal depolarization. Here it is shown that the ciliary CNG channels also open spontaneously. In the absence of odorants and second messengers, olfactory cilia have a small basal conductance to cations. Part of this conductance is similar to the cAMP-activated conductance in its sensitivity to channel inhibitors and divalent cations. The basal conductance may help to stabilize the neuronal membrane potential while limiting the sensitivity of odorant detection.
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, University of Cincinnati, PO Box 670667, Cincinnati, OH 45267-0667, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Kleene
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000584:Amiloride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002413:Cations, Divalent; D000242:Cyclic AMP / Q000378:metabolism; D054815:Cyclic Nucleotide-Gated Cation Channels; D004110:Diltiazem / Q000494:pharmacology; D004553:Electric Conductivity; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008274:Magnesium / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009831:Olfactory Mucosa / Q000166:cytology; D011894:Rana pipiens; D015290:Second Messenger Systems; D026941:Sodium Channel Blockers; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D002413:Cations, Divalent; D054815:Cyclic Nucleotide-Gated Cation Channels; D004791:Enzyme Inhibitors; D007473:Ion Channels; D026941:Sodium Channel Blockers; D013449:Sulfonamides; C041470:3',4'-dichlorobenzamil; C017967:W 7; D000584:Amiloride; D000242:Cyclic AMP; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004110:Diltiazem; D008274:Magnesium; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine