Fig. 8. Effects of the selective GABA_B agonist baclofen (0.5 µmol l^–1) on the lung burst frequency responses to hypoxia in (A) the pre-metamorphic group and (B) adult group. Responses were measured under control (drug-free) conditions (N=7, in each group) and in the presence of baclofen (N=6, in each group). Note that in these figures, the control data (grey symbols, broken lines) were transposed from Fig. 1 to facilitate comparisons. Trigeminal neurograms (V, trigeminal nerve) presented below show representative respiratory-related activity recorded under each condition. Values are means ± s.e.m. ^*Values statistically different from baseline at P<0.05.