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Chem Senses

Title:		Maxillary palps are broad spectrum odorant detectors in Culex quinquefasciatus
Author(s):		Syed Z; Leal WS;
Address:		"Honorary Maeda-Duffey Lab, Department of Entomology, University of California-Davis, Davis, CA 95616, USA"
Journal Title:		Chem Senses
Year:		2007
Volume:		20070614
Issue:		8
Page Number:		727 - 738
DOI:		10.1093/chemse/bjm040
ISSN/ISBN:		0379-864X (Print) 0379-864X (Linking)
Abstract:		"A single type of olfactory sensilla on maxillary palps in many species of mosquitoes houses a very sensitive olfactory receptor neuron (ORN) for carbon dioxide reception. We performed extensive single sensillum recordings from this peg sensillum in Culex quinquefasciatus and have characterized the response threshold and kinetics for CO(2) reception, with a detection threshold less than the CO(2) concentration in the atmosphere. This ORN responded in a tonic mode to lower concentrations of CO(2), whereas higher concentrations generated a phasic-tonic mode of action potential firing. Sensillum potentials accurately represented the response magnitude and kinetics of carbon dioxide-elicited excitatory responses. Stimulation of these ORNs with human breath, a complex mixture of mosquito kairomones and up to 4.5% CO(2), elicited excitatory responses that were reliably detected by CO(2)-sensitive ORNs. Another ORN housed in these sensilla responded to 1-octen-3-ol and to various plant-derived compounds, particularly floral and green leaf volatiles. This ORN showed remarkable sensitivity to the natural enantiomer, (R)-(-)-1-octen-3-ol, rivaling pheromone-detecting ORNs in moths. Maximum neuronal response was elicited with a 10 ng dose. A biological, ecological role of maxillary palps in detection of plant- and nectar-related sources is proposed"
Keywords:		"Animals Carbon Dioxide/metabolism Culex/*physiology Culicidae Dose-Response Relationship, Drug Electrophysiology Female Humans Kinetics Male Microscopy, Electron, Scanning Neurons/metabolism Odorants Olfactory Pathways/*metabolism Olfactory Receptor Neuro;"
Notes:		"MedlineSyed, Zainulabeuddin Leal, Walter S eng U01AI05826-01/AI/NIAID NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't England 2007/06/16 Chem Senses. 2007 Oct; 32(8):727-38. doi: 10.1093/chemse/bjm040. Epub 2007 Jun 14"