Fig. 7

Effect of GK-6 (a) and GK-2 (b) on the pain thresholds in rats measured by the immersion “tail flick” test. The dipeptide GK-2 was administered i.p. at doses of 0.5, 1 and 2 mg/kg. Noxious stimuli were applied by immersing the distal third of each rat's tail in hot water (55±0.2ºC). Tail flick latency was measured before (baseline level) and 30, 60 min and 24 h after GK-2 administration. The time intervals were selected based on data related to NGF-induced hyperalgesia. Data are presented as means±S.E.M. * p < 0.05, ** p < 0.01, *** p .0.001 compared to the control group (Mann–Whitney U test)