(a, b) NEM and PEM innervation is compromised in Ret-deficient mice. Triple immunohistochemistry for ASMACy3, TH and K5 on NEM sections (a) and for ASMACy3 and TH in PEM sections (b) from P11 control and mutant mice. NEM and PEM of Ret-deficient mice display decreased innervation, compared to control animals. (c) Deletion of Ret in the noradrenergic, but not cholinergic, sympathetic lineage was achieved by driving Cre from the TrkA locus. Triple immunohistochemistry for RET, GFP (recapitulating Ret expression) and TRKA on SG sections from P11 control Retfl/CFP and mutant TrkACre/+;Retfl/CFP mice. RET protein is detectable in RetCFP+TRKA+ EMNs of control (RET+RetCFP+TRKA+ neurons, arrowheads), but not mutant SG neurons (RET-RetCFP+TRKA+ neurons, arrowheads). However, note that RET is still expressed in TRKA- cholinergic neurons (asterisks). (d) Comparison of soma size of NPY+TH+ and CDH8+TH+ (NA4/5) individual neurons (1 dot = 1 neuron) of control Retfl/fl and mutant TrkACre/+;Retfl/fl mice from Fig. 5p confirms that Ret deletion affects soma size of EMN but not of other noradrenergic neurons (NPY+TH+ cells: t(215) = 1.049, P = 0.2954, unpaired t test, n=112 for Retfl/fl and n=105 for TrkACre/+;Retfl/fl; CDH8+TH+ cells: t(267) = 5.588, P < 0.0001, unpaired t test, n=131 for Retfl/fl and n=138 for TrkACre/+;Retfl/fl). (c) are representative images from experiments carried out on at least two animals. Scale bar: 50 μm in (a), 20 μm in (b) and (c).