Fig. 4. Ruthenium Red (RR), an antagonist of the IP₃R, fails to block chemosignal-activated currents in S. odoratus vomeronasal sensory neurons (VSNs) while an inhibitor of phospholipase C (U73122) does block chemosignal-activated currents. (A) A representative example of the response of a female VSN to catfish extract at 0 min (top trace) and 6 min later (bottom trace) without pharmacological perturbation. The chemosignal presentation is shown as black bar above the response. This particular cell was used primarily for reversal potential analysis, hence the VSN had been exposed to the chemical signal twelve times within the time span described. (B) Histogram plot of the normalized current magnitude (normalized to first exposure to chemosignal; t₀) over time. Cells were sampled at varying time points (t_n), such that not every cell was sampled for each of the time points. The amplitude of the chemosignal-activated current was not altered over 12 min (one-way repeated measures ANOVA, P0.05). (C) A representative example of the response of a female VSN to male urine at 0 min (top trace) and 6 min (bottom trace) following bath application of 1 mmol 1^–1 RR. (D) Histogram plot of the normalized current magnitude (normalized to t₀) over time. The chemosignal-activated current is not altered over 10 min (not significantly different by treatment or time, two-way repeated measures ANOVA, P0.05) in response to RR treatment. The normal chemosignal response over time is denoted by the broken line. (E) A representative example of the response of a female VSN to catfish extract at 0 min (top trace) and 8 min (bottom trace) following bath application of 50 µmol l^–1 U73122. (F) As in D but for U73122 treatment. Asterisks denote significant difference between treatments, two-way repeated measures ANOVA, followed by SNK pairwise multiple comparison between treatment and time, P0.05). N values are shown beside bars. (A,C,E) Broken line denotes baseline current.