Fig. 4. Integrated multiunit recordings obtained from a single electrode location in the sensory epithelium to: (A) control (C) and 0.1 mmol l^–1 L-arginine (Arg); (B) putrescine, (C) cadaverine and (D) spermine (inset shows an example of spermine decreasing background neural activity). (E) The chart indicates the median (filled circle) and range (horizontal bar) of estimated electrophysiological thresholds (mol l^–1) to putrescine (Put; N=5 fish), cadaverine (Cad; N=5) and spermine (Spe; N=2). Odorant concentrations (mol l^–1) in A–D are listed below each trace.