Odorant responses of dual polarity are mediated by cAMP in mouse olfactory sensory neurons.
Some olfactory sensory neurons (OSNs) respond to odors with hyperpolarization. Although transduction for excitatory responses is mediated by opening of a cyclic nucleotide-gated (CNG) channel, there is controversy on the mechanism underlying inhibitory responses. We find that mouse OSNs respond to odorants by either depolarizing or hyperpolarizing responses in loose-patch measurements. In the perforated-patch configuration, OSNs not only responded with a current consistent with CNG channel-mediated excitation but also displayed enhancement of outward currents, consistent with inhibitory responses. Increasing cAMP levels pharmacologically elicited excitatory or inhibitory responses in different OSNs. In addition, OSNs from mice defective for the CNGA2 subunit of the CNG channel displayed neither excitatory nor inhibitory responses. Thus CNG channels mediate inhibitory olfactory responses.
104 Marsh Life Science, Biology Dept., University of Vermont, Burlington, VT 05405, USA. rona.delay@uvm.edu
Rona
R
Delay
Diego
D
Restrepo
D000818:Animals; D000242:Cyclic AMP / Q000502:physiology*; D054815:Cyclic Nucleotide-Gated Cation Channels; D005260:Female; D007473:Ion Channels / Q000096:biosynthesis / Q000172:deficiency; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D018035:Receptors, Odorant / Q000502:physiology*
D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels; D018035:Receptors, Odorant; D000242:Cyclic AMP