Extended Data Fig. 6: Myenteric responses to CCK8, GLP-1 and 5-HT in the small intestine.

a–f, Myenteric responses to intravillus injection of agonists in duodenum (a,c,d) and terminal ileum (b,e,f) full-thickness preparations. While 5-HT (10 µM) evoked neuronal responses in myenteric neurons of both gut regions (d, n = 10 villi examined; f, n = 6 villi; responders indicated by arrowheads), no responses were observed to (c) CCK8 applied into villi of the duodenum (n = 12 villi) or to (e) GLP-1 in the villi of terminal ileum (n = 12 villi). The traces in the panels on the right show changes in fluorescence intensity over time for neurons indicated by filled arrowheads (responders) or empty arrowheads (non-responders). g–j, CCK8 (100 nM) or GLP-1 (100 nM) were also applied directly onto myenteric ganglia in peeled jejunum LMMP preparations by pressure ejection from a micropipette at t = 10 s. g,g’, Two CCK8 applications (separated by a 5 min Krebs washout) evoked reproducible responses in a subset of myenteric neurons (n = 10 FOVs examined). h,h’, Responses to GLP-1 (two applications separated by a 5 min Krebs washout) were less reproducible with only a small percentage of total neurons responding to both applications (n = 8 FOVs examined). i, Some CCK8-responsive neurons as indicated by arrowheads (left, middle) and corresponding Ca²⁺ transients (right). j, Some GLP-1-responsive myenteric neurons as indicated by arrowheads (left, middle) and corresponding Ca²⁺ transients (right). Scale bars, 20 µm. Data are mean ± s.e.m. Drawings in a and g are adapted from ref. ³⁰ (Wiley).

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