In Vivo Responses of Single Olfactory Receptor Neurons of Channel Catfish
to Binary Mixtures of Amino Acids.
Kang, Jiesheng and John Caprio.
Department of Zoology and Physiology, Louisiana State University, Baton
Rouge, LA. 70803-1725.
APStracts 3:0207N, 1996.
For the first time in any vertebrate, in vivo responses of single olfactory
receptor neurons to odorant mixtures were studied quantitatively.
Extracellular electrophysiological responses of 54 single olfactory receptor
neurons from 23 channel catfish, Ictalurus punctatus , to binary mixtures of
amino acids and to their components were recorded simultaneously with the
electro-olfactogram (EOG). For 57% (73 of 128) of the tests, no significant
change (N) from spontaneous activity occurred. Responses to the remaining 55
tests of binary mixtures were excitatory (E; 13%) or suppressive (S; 30%). No
response type was associated with any specific mixture across the neurons
sampled. Eighty-six percent of the responses of catfish olfactory receptor
neurons to binary mixtures were classified similar to at least one of the
component responses, a percentage comparable (i.e. 89%) to that observed for
single olfactory bulb neurons in the same species to equivalent binary
mixtures. The responses of single olfactory receptor neurons to component-
similar binary mixtures (i.e. component responses were both E, both S and both
N, respectively) were generally (80% of 59 tests) classified similar to the
responses to the components. For E+N and S+N binary mixtures, the N component
often (66% of 58 tests) reduced or concealed (i.e. "masked") the excitatory
and suppressive responses, respectively. For the majority (6 of 11 tests) of
E+S binary mixtures, null activity resulted. Responses to the remaining five
tests were either excitatory (n=3) or suppressive (n=2).
Received 3 May 1996; accepted in final form 9 September 1996.
APS Manuscript Number J364-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996