Fig. 2.

Vestibular response enhancement at low doses of XE991. A: VsEP response waveforms shown were recorded before (B, baseline) and 20 and 40 min after a dose of 0.5 mg/kg XE991. Notice the shortening of latencies for all peaks (P1, N1, P2) at 20 and 40 min after injection. A modest increase in amplitudes for P1-N1 is present as well. Calibration bars indicate 1.0 ms and 2.0 μV for graphic. Dashed vertical lines identify latencies of P1, N1, and P2 before drug injection. Stimulus level was 6 dB re:1 g/ms. B: mean values during enhancement of vestibular responses following low doses of XE991 (0.5 and 1.0 mg/kg). Values are normalized to baseline mean value for responses before injection. Values are mean changes (difference) from baseline (0) for response latencies (P1, N1; in μs) and amplitudes (P1-N1; in μV) over time for each dose group indicated. Significant reduction in latencies and increased amplitudes were found for 0.5 and 1.0 mg/kg only. Dose groups are represented by different colors as follows: 0.05 (dark green; n = 5), 0.5 (dark red; n = 5), and 1 mg/kg (dark blue; n = 6) and saline (black; n = 5). These low doses of XE991 led to decreased VsEP peripheral latencies (P1, N1) and increased amplitudes (P1-N1) systematically. Time 0 is time of XE991 injection. Data at left of vertical dashed lines represent the baseline period before drug administration, and data at right indicate drug effects after drug injection. Stimulus level was 6 dB re: 1.0 g/ms.