Figure 5. CCK^NTS and DBH^NTS neurons send direct, excitatory input to CGRP^PBN neurons.

(a) Representative immunohistological image from the PBN showing CCK fibre terminals in red and CGRP-expressing cell nuclei in green after injecting AAV1-DIO-synaptophysin:mCherry into the NTS of a Cck^Cre/+::Calca^Cre:GFP/+ mouse. Scale bar, 100 μm. (b) Live imaging of the lateral PBN before electrophysiological recording in a Dbh^Cre/+::Calca^Cre:GFP/+ mouse. Red fibres, from DBH^NTS neurons targeted for photostimulation and green nuclei indicate CGRP^PBN neurons targeted for recording. Scale bar 20 μm. (c,d) Action potentials recorded in cell-attached configuration and evoked in CGRP^PBN neurons by stimulation of CCK^NTS (c) and DBH^NTS (d) axons by pulses of blue light indicated by blue bars. (e,f) Synaptic currents in CGRP^PBN neurons following stimulation of CCK^NTS (e) and DBH^NTS (f) inputs by pulses of blue light indicated by blue bars. (g) Individual jitter values for synaptic currents in CGRP^PBN neurons represented in e and f. (h,i) Representative traces from synaptic currents in CGRP^PBN neurons, following stimulation of CCK^NTS (h) and DBH^NTS (i) inputs were reversibly inhibited by 20 μM CNQX and 100 μM D-AP5. (j) Quantitative effect of 20 μM CNQX and 100 μM D-AP5 (block) on synaptic currents represented in h,i. All currents were recorded in the presence of 100 μM picrotoxin.