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J Comp Physiol A Neuroethol Sens Neural Behav Physiol

Title:		Olfactory perireceptor and receptor events in moths: a kinetic model revised
Author(s):		Kaissling KE;
Address:		"Max-Planck-Institut fuer Verhaltensphysiologie/Ornithologie, Seewiesen, 82319, Starnberg, Germany. Kaissling@orn.mpg.de"
Journal Title:		J Comp Physiol A Neuroethol Sens Neural Behav Physiol
Year:		2009
Volume:		20090821
Issue:		10
Page Number:		895 - 922
DOI:		10.1007/s00359-009-0461-4
ISSN/ISBN:		1432-1351 (Electronic) 0340-7594 (Print) 0340-7594 (Linking)
Abstract:		"Modelling reveals that within about 3 ms after entering the sensillum lymph, 17% of total pheromone is enzymatically degraded while 83% is bound to the pheromone-binding protein (PBP) and thereby largely protected from enzymatic degradation. The latter proceeds within minutes, 20,000-fold more slowly than with the free pheromone. In vivo the complex pheromone-PBP interacts with the receptor molecule. At weak stimulation the half-life of the active complex is 0.8 s due to the postulated pheromone deactivation. Most likely this process is enzymatically catalysed; it changes the PBP into a scavenger form, possibly by interference with the C-terminus. The indirectly determined PBP concentration (3.8 mM) is close to direct measurements. The calculated density of receptor molecules within the plasma membrane of the receptor neuron reaches up to 6,000 units per mum(2). This is compared with the estimated densities of the sensory-neuron membrane protein and of ion channels. The EC(50) of the model pheromone-PBP complex interacting with the receptor molecules is 6.8 muM, as compared with the EC(50) = 1.5 muM of bombykol recently determined using heterologous expression. A possible mechanism widening the range of stimulus intensities covered by the dose-response curve of the receptor-potential is proposed"
Keywords:		"Animals Biological Transport Carrier Proteins/*metabolism Computer Simulation Fatty Alcohols/metabolism Insect Proteins/*metabolism Kinetics *Models, Biological Moths/*physiology Pheromones/*metabolism Protein Conformation Receptors, Odorant/*metabolism *;"
Notes:		"MedlineKaissling, Karl-Ernst eng Review Germany 2009/08/22 J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2009 Oct; 195(10):895-922. doi: 10.1007/s00359-009-0461-4. Epub 2009 Aug 21"