Journal of Neurophysiology, Vol 66, Issue 1 112-130, Copyright © 1991 by APS

ARTICLES

Responses of olfactory receptor cells of spiny lobsters to binary mixtures. I. Intensity mixture interactions

C. D. Derby, M. N. Girardot and P. C. Daniel
Department of Biology, Georgia State University, Atlanta 30302-4010.

1. Neural coding of chemical mixtures was studied with the use of the peripheral olfactory system of the spiny lobster. The occurrence of mixture interactions (i.e., where the observed response to a mixture deviates significantly from the expected response) in individual cells and the effect of such mixture interactions on the coding of odorant intensity by populations of cells were examined. 2. Extracellular recordings of spiking activity of 98 primary olfactory receptor cells in the antennules were measured in response to seven compounds [adenosine-5'-monophosphate (AMP), betaine (Bet), L-cysteine (Cys), L-glutamate (Glu), ammonium chloride (NH4), DL-succinate (Suc), and taurine (Tau)] and their binary mixtures. To identify mixture interactions, observed responses to a range of concentrations of a binary mixture were compared with the predicted responses based on three mathematical models: a single receptor model, which assumes that the two compounds of a mixture bind to the same receptor site; a multiple receptor model, which assumes that the two compounds bind to two independent receptor sites; and a mixed composition receptor model, which incorporates our current state of knowledge of transduction processes in olfactory receptor cells of spiny lobsters. 3. Mixture interactions in individual cells were common: statistically significant mixture interactions were observed in 25% of the possible cases (Fig. 5). Suppression was much more common than enhancement. 4. Mixture interactions had significant effects on the absolute response magnitudes for a population of cells, which could be used as the neural code for stimulus intensity in this system. These effects are called intensity mixture interactions (Figs. 6-11). Intensity mixture interactions occurred for approximately 50% of the binary mixtures and were almost exclusively suppression (Figs. 12 and 13). The intensity mixture interactions were concentration independent. 5. The results suggest that mixture interactions in individual olfactory cells can result in intensity mixture interactions in the neuronal population such that there is a decrease in sensitivity to binary mixtures relative to what is expected based on the responses to individual components of the mixtures.

This article has been cited by other articles:

				D. Mellon Jr Combining Dissimilar Senses: Central Processing of Hydrodynamic and Chemosensory Inputs in Aquatic Crustaceans Biol. Bull., August 1, 2007; 213(1): 1 - 11. [Abstract] [Full Text] [PDF]

				M. Schmidt and C. D. Derby Non-olfactory chemoreceptors in asymmetric setae activate antennular grooming behavior in the Caribbean spiny lobster Panulirus argus J. Exp. Biol., January 15, 2005; 208(2): 233 - 248. [Abstract] [Full Text] [PDF]

				P. Steullet, D. R. Krutzfeldt, G. Hamidani, T. Flavus, V. Ngo, and C. D. Derby Dual antennular chemosensory pathways mediate odor-associative learning and odor discrimination in the Caribbean spiny lobster Panulirus argus J. Exp. Biol., March 15, 2002; 205(6): 851 - 867. [Abstract] [Full Text] [PDF]

				L. Belluscio and L. C. Katz Symmetry, Stereotypy, and Topography of Odorant Representations in Mouse Olfactory Bulbs J. Neurosci., March 15, 2001; 21(6): 2113 - 2122. [Abstract] [Full Text] [PDF]

				H. Yamada and K. Nakatani Odorant-induced Hyperpolarization and Suppression of cAMP-activated Current in Newt Olfactory Receptor Neurons Chem Senses, January 1, 2001; 26(1): 25 - 34. [Abstract] [Full Text] [PDF]

				J. Kang and J. Caprio In Vivo Responses of Single Olfactory Receptor Neurons of Channel Catfish to Binary Mixtures of Amino Acids J Neurophysiol, January 1, 1997; 77(1): 1 - 8. [Abstract] [Full Text] [PDF]