Figure 5. Sulfate conjugates account for a large percentage of BALB/c female physiological activity and greatly exceed the activity of previously-reported VSN ligands.

(A) The firing rates recorded on a sample electrode are shown in response to control and enzymatically-digested stimuli. Firing rate increased greatly to treatments without sulfatase (-sulf) and either with (+glucur) or without (-glucur) glucoronidase. In contrast, treatment with sulfatase (+sulf) nearly abolished the response. The black bars represent the stimulus timing.

(B) Multi-unit activity evoked by sulfatase-treated ODS-urine extract compared against mock-treated extract (90 electrodes from 6 preparations), revealing that the majority of activity in urine is sensitive to sulfatase digestion. Inset: percentage of overall activity retained after digestion.

(C) Multi-unit activity evoked by β-glucuronidase-treated ODS-urine extract compared against mock-treated extract (90 electrodes from 6 preparations), indicating that the majority of activity is resistant to digestion by glucuronidase

(D-I) Multiunit recordings of neural responses to 6 compounds: cort21S (D, 360 electrodes, 50 and 100μM), A7010 (E, 300 electrodes, 50 and 100μM), ESP1 (F, 540 electrodes, 0.1μM; these multiunit data included for comparability, a detailed study of the single units isolated from these electrodes was reported in Kimoto et al., 2007), SYFPEITHI (G, 480 electrodes, 0.1 and 1 μM), 2-heptanone (H, 540 electrodes, 100μM), muscone (I, 360 electrodes, 100μM). In D-I, all recorded electrodes are shown; the percentage of responsive electrodes is presented in Table 1.