Rapid habituation of a touch-induced escape response in Zebrafish (Danio rerio) Larvae
Fig 5
Strychnine blocks habituation to touch by disrupting the escape response.
(a) Effect of strychnine (100 μM; StrychTC, n = 7) or vehicle (E3TC, n = 6) on the nonhabituated escape response of larvae. A repeated measure between-groups ANOVA revealed a significant interaction between these groups (F[4, 44] = 5.077; p < 0.05). Posthoc revealed that the differences in abnormal responses between the StrychTC and E3TC groups were significant for the 60-min (StrychTC, 0.50 ± 0.19; E3TC, 0.00 ± 0.00), and 75-min posttests (StrychTC, 0.50 ± 0.19; E3TC, 0.00 ± 0.00) (p < 0.05), but not for the 15-min (StrychTC, 0.13 ± 0.13; E3TC, 0.00 ± 0.00), 30-min (StrychTC, 0.00 ± 0.00; E3TC, 0.00 ± 0.00), or 45-min posttests (StrychTC, 0.43 ± 0.20; E3TC, 0.00 ± 0.00) (p > 0.05). (b) Effect of strychnine on habituation of the escape response. To determine whether the altered startle response observed in strychnine-treated fish could still undergo habituation, we exposed groups to strychnine (StrychT, n = 6) or vehicle (E3T, n = 8) for 18–24 h prior to the onset of behavioral testing/training. One minute after habituation training, the StrychT group was significantly (t [12] = 2.93; p < 0.05) more responsive than the E3T group. (c) Comparison of the effects of strychnine on fish that did not receive habituation training. The difference between the group treated with strychnine for 18–24 h (StrychUT, n = 8) and the group treated with vehicle (E3UT, n = 8) was not significant (t [14] = 1.53; p = 0.15).