Fig. 2
From: A subpopulation of projections from the parabrachial nucleus to the central amygdala mediates itch
Serotonin-responsive projection neurons from the PBN to the CeA are predominantly non-CGRP⁺. (A) Schematic timeline outlining the experimental protocol. (B) Schematic representation of the experimental procedure. Serotonin-TRAPed mice received unilateral intra-CeA injections of cholera toxin subunit B (CTB). Coronal sections including the PBN were collected for analysis. (C) Representative coronal section of the PBN, showing serotonin-TRAPed neurons (red), CGRP⁺ neurons (green), and CeA-projecting neurons (cyan). Scale bar, 100 μm. (D) Magnified view of the region outlined in panel C, focusing on the PBN lateral external (PBNLE) subregion. Scale bar, 100 μm. (E) Pie chart: Of 727 total TRAPed (tdTomato⁺) neurons identified in the lateral PBN (from 3 mice, 3 sections per mouse), 28.3% (206 neurons) projected to the CeA. (F) Pie chart: Among 542 CGRP⁺ neurons in the PBNLE, 8% (44 neurons) were TRAPed. (G) Pie chart: Of the 121 TRAPed neurons within the PBNLE, 36.3% (44 neurons) co-expressed CGRP. (H) Pie chart: Among the 67 TRAPed neurons that projected to the CeA within the PBNLE, 47.8% (32 neurons) were CGRP⁺.
