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Fig. 2. Whole-mount in situ hybridization illustrating the expression
of PACAP (A–I) and PAC1 (J–O) genes in embryos at different
developing stages. A–I show PACAP mRNA distribution in embryos
at stage 18, 21, 23, 25, 26, 27, 29, 31, and 33, respectively. PACAP
mRNA signals were first localized at stage 21 in the embryonic spinal
cord (small arrow in B). At the later stages, PACAP mRNA signals
were continuously detected in the dorsal part of the entire spinal cord
and middle/posterior rhombencephalon (small arrows in B–I). Hybridization
signals were not present in the embryonic forebrain over the
course of study (open arrows in D–H). Starting from stage 23 (C),
however, PACAP gene transcripts were observed in the trigeminal
ganglia (large arrows in C–H). J–O show PAC1 mRNA distribution in
embryos at stage 18, 21, 26, 28, 31, and 33, respectively. PAC1 mRNA
signals were first detected in the forebrain area at stage 21 (solid
arrow in K). At the later stages, PAC1 mRNA signals were continuously
detected in deep portions of the forebrain, including the tuberculum
posterior, prosencephalon, mesencephalon, rhombencephalon,
and anterior spinal cord (solid arrows in L–O). PAC1 gene transcripts
were not discernible in the forebrain of embryos at stages 18 (open
arrow in J) or in the middle/posterior spinal cord at any stage (open
arrows in K–O). SC, spinal cord; F, forebrain; TG, trigeminal ganglion.
Scale bar 5 2 mm. |