Fig. 4

Effects of i.p. injection of DOI and ketanserin on tidal volume response to hypoxia in the intact rats (a) and two weeks after lesion with 6-OHDA (b). Effects of i.p. injection of DOI and ketanserin on frequency of breathing response to hypoxia in the intact state (c) and two weeks after lesion (d). Effects of i.p. injection of DOI and ketanserin on minute ventilation response to hypoxia in the intact rats (e) and two weeks after lesion with 6-OHDA (f). The data are expressed as percentage of change in reference to normoxic value considered as 100%. All values are means ± SEM. *P < 0.05, ***P < 0.001, versus the respective pre-hypoxic baseline value; ^# P < 0.05, ^## P < 0.01, ^### P < 0.001, versus the corresponding control and post-ketanserin value; ⁺ P < 0.05, ⁺⁺ P < 0.01, versus the corresponding post-ketanserin value (n = 9)