| Title: | Cyclic nucleotide-dependent ionic currents in olfactory receptor neurons of the hawkmoth Manduca sexta suggest pull-push sensitivity modulation |
| Author(s): | Dolzer J; Schroder K; Stengl M; |
| Address: | "Biologie, Tierphysiologie, Philipps-Universitat Marburg, Marburg, Germany. Institut fur Zoologie, Universitat Regensburg, Regensburg, Germany. Animal Physiology/Neuroethology, Biology, FB 10, University of Kassel, Kassel, Germany" |
| ISSN/ISBN: | 1460-9568 (Electronic) 0953-816X (Linking) |
| Abstract: | "Olfactory receptor neurons (ORNs) of the hawkmoth Manduca sexta sensitize via cAMP- and adapt via cGMP-dependent mechanisms. Perforated patch clamp recordings distinguished 11 currents in these ORNs. Derivatives of cAMP and/or cGMP antagonistically affected three of five K(+) currents and two non-specific cation currents. The Ca(2+) -dependent K(+) current I(K(Ca)(2+)()) and the sensitive pheromone-dependent K(+) current I(K(cGMP-)) , which both express fast kinetics, were inhibited by 8bcGMP, while a slow K(+) current, I(K(cGMP+)) , was activated by 8bcGMP. Furthermore, application of 8bcAMP blocked slowly activating, zero mV-reversing, non-specific cation currents, I(LL) and I(cat(PKC?)) , which remained activated in the presence of 8bcGMP. Their activations pull the membrane potential towards their 0-mV reversal potentials, in addition to increasing intracellular Ca(2+) levels voltage- and I(LL) -dependently. Twenty minutes after application, 8bcGMP blocked a TEA-independent K(+) current, I(K(noTEA)) , and a fast cation current, I(cat(nRP)) , which both shift the membrane potential to negative values. We conclude that conditions of sensitization are maintained at high levels of cAMP, via specific opening/closure of ion channels that allow for fast kinetics, hyperpolarized membrane potentials, and low intracellular Ca(2+) levels. In contrast, adaptation is supported via cGMP, which antagonizes cAMP, opening Ca(2+) -permeable channels with slow kinetics that stabilize depolarized resting potentials. The antagonistic modulation of peripheral sensory neurons by cAMP or cGMP is reminiscent of pull-push mechanisms of neuromodulation at central synapses underlying metaplasticity" |
| Keywords: | "Animals Calcium *Manduca Membrane Potentials Nucleotides, Cyclic *Olfactory Receptor Neurons Sensory Receptor Cells cAMP cGMP insects metaplasticity olfactory transduction;" |
| Notes: | "MedlineDolzer, Jan Schroder, Katrin Stengl, Monika eng Research Support, Non-U.S. Gov't France 2021/06/16 Eur J Neurosci. 2021 Aug; 54(3):4804-4826. doi: 10.1111/ejn.15346. Epub 2021 Jul 8" |
