Figure 4.

Acute nociceptive responses of wild-type(+/+), heterozygote (+/−), and homozygous mutant mice (−/−). (A) Fifty percent hindpaw withdrawal thresholds to stimulation with von Frey hairs (+/+, n = 13; +/−, n = 21; −/−, n = 24). (B) Hindpaw withdrawal latencies to noxious thermal stimuli with a low intensity (open columns) and a high intensity (filled columns). +/+, n = 13, 12; +/−, n = 21, 16; −/−, n = 24, 15 at low and high intensities, respectively. (C) Tail flick latencies to noxious heat (48–49°C; +/+, n = 12; +/−, n = 17; −/−, n = 15). (D) Hindpaw licking latencies in the hot plate tests (+/+, n = 11; +/−, n = 17; −/−, n = 15) at 50 °C (open columns), 52 °C (filled columns), and 55 °C (gray columns). There are no significant differences in these four tests across the three genotypes.