Fig. 5

Measurement of CTA induced by l-histidine administration. a Amount of fluid intake per rat body weights in each experimental group (the control group, n = 5; l-histidine 0.75 g/kg group, n = 6; l-histidine 2.0 g/kg group, n = 5) from day 7 (the last training day) to day 14 in the CTA measurement schedule. Proportion of saccharin intake and DW intake is indicated in each column. b Amount of saccharin intake per rat body weights in each experimental group on day 8 (the conditioning day) and day 10 (the control group, n = 5; l-histidine 0.75 g/kg group, n = 6; l-histidine 2.0 g/kg group, n = 5). *p < 0.05 compared with the control group. ^† p < 0.05 compared with l-histidine 0.75 g/kg group (Tukey–Kramer’s test). c Saccharin preference in each experimental group on day 10 (saccharin intake/total fluid intake). *p < 0.05 compared with the control group (Tukey–Kramer’s test)