Fig. 5.

Evidence that TrkB signalling mediates BDNF regulation of fetal preBötC neuron activity. (A) Bar histograms showing the mean firing frequency of preBötC neurons (n = 5; extracellular activity from five preparations) in control (CTL) conditions (white bars), in the presence of 200 nM K252a for 1 h (light grey bar) and in the presence of 200 nM K252a plus 100 ng/mL BDNF for 15 min (black bar) following 1 h pretreatment with the tyrosine kinase inhibitor alone. In contrast to the increase in frequency observed in response to BDNF alone (Fig. 1), BDNF had no effect in the presence of K252a, consistent with a requirement for tyrosine kinase activation. (B) Agarose gel analysis of reverse transcription-PCR products amplified from two different rhythmic neurons. Φ and M correspond to molecular weight markers (indicated on the left and right of the gel). (C) Bar graph representing the proportion of TrkB-positive neurons expressing other markers, including HCNs, VGlut2, μ receptor, p75 receptor and NK1R.