Mechanisms for mixture suppression in olfactory receptors of the spiny lobster

The mechanisms by which the output of olfactory receptor cellsis suppressed, as can happen, for example, when receptor cellsare activated by stimulus mixtures, are ill defined. We showthat subthreshold concentrations of some odorants suppress theresponses of antennular (olfactory) chemoreceptors of the spinylobster to stimulatory odorants in a manner indicative of competitiveinhibition. The effect of these suppressive odorants on theresponse of other receptor cells is inconsistent with this hypothesis,allowing that non-competitive mechanisms also contribute toperipheral mixture suppression in the olfactory pathway of thespiny lobster.