Spectral tuning properties of chemoreceptor cells in the front walking legs of the common spider crab Libinia emarginata

Chemoreceptor cells in the front walking legs of the common spider crab Libinia emarginata serve among other functions, in chemical recognition of food. Based upon extracellular recordings of action potentials, we report on 49 cells identified with a 19-compound equimolar mixture of amino acids and a few other compounds used in previous studies of decapod chemoreceptors. All cells were tested with each compound separately with 1 second pulses at 10(-3) M. Twenty-seven percent of all cells responded best to glycine, 18% to glutamate, and 16% to taurine. Other cells responded strongest to putrescine, hydroxyproline, ammonium, valine, leucine, and arginine. Individual cells generally had an intermediate tuning breadth. As a chemoreceptor organ the walking leg of L. emarginata contained several best cell populations and was not dominated by a particular best cell population.