Figure 8.

Illustration of respiratory modulation evoked by glutamate and BDNF microinjections into the KF in the perfused brainstem preparation derived from different postnatal stages A Illustrates that microinjections of glutamate in the intermediate group evoked apnoea while subsequent BDNF injection was ineffective. In contrast, at juvenile stages (B) BDNF evoked brief apnoeas similar to those observed after the preceding glutamate injections. C, bar graphs summarize the statistical analysis of the glutamate- and BDNF-evoked prolongation of the expiratory interval (t_E) in the intermediate and juvenile age group (left). Developmental comparison of the BDNF-induced effect on t_E is shown in the right diagram. *P < 0.05, ***P < 0.001. D, photomicrographs illustrating examples of the localization of injection sites for the intermediate and juvenile groups. Abbreviations: PNA, phrenic nerve activity; 5N, motor trigeminal nucleus; KF, Kölliker–Fuse nucleus; ll, lateral lemniscus; LPB, lateral parabrachial nucleus; Me5, mesencephalic trigeminal nucleus; MPB, medial parabrachial nucleus; Pr5, principal sensory trigeminal nucleus; scp, superior cerebellar peduncle.