The sympathies of the body: functional organization and neuronal differentiation in the peripheral sympathetic nervous system

Figures

• 

  Fig. 1. Regulatory domains in homeostatic demands, employed neurotransmitter systems and target tissues innervated by sympathetic postganglionic efferents. The figure displays the sympathetic transmitter systems employed in different target tissues. blue, noradrenergic; red, cholinergic. The data have been obtained by immunehistological detection of tyrosine hydroxylase as key marker for noradrenergic sympathetic neurons and by pharmacological discrimination of noradrenergic versus cholinergic activator or inhibitor-mediated actions. In the case of rodent sweat glands, also immunohistochemistry for choline acetyltransferase and the vesicular acetylcholine transporter have been employed in combination with retrograde labeling. Abbreviations: aa, arteries and arterioles; BAT, brown adipose tissue; MSCN: marrow stem cell niche; OST: osteoblast/osteoclast; Pancr., Pancreatic; LT: lymphatic tissue; WAT: white adipose tissue

• 

  Fig. 2. Expression of growth factor receptors and synaptic organizers of the protocadherin gene family in mouse thoracic sympathetic neuron classes. Expression level for the genes encoding the indicated receptor and organizer genes at larger than 0 (grey), 2 (yellow), 4 (orange), 8 (red), or 16 (dark red) mRNA molecules per cell. Data are taken from Furlan et al. (2016). While all noradrenergic neuron subpopulations (NA 1–5) show strong TRKA expression, the cholinergic sympathetic neurons show abundant RET expression. However, RET transcripts are detected in all, also noradrenergic sympathetic neuron classes. This observation was also made by quantitative density analysis of NBT/BCIP signals obtained from in situ hybridization in mouse cervical and thoracic sympathetic ganglia (UE, unpublished). Transcripts for GFRa receptor subunits can be detected at relatively low levels. GFRa1 and GFRa4 transcripts are not or barely observed (not displayed). GFRa3 is detected at very low levels in NA 1–5 but not in ACH 1 and ACH 2. Only GFRa2 is observed in significant levels in the cholinergic neuron populations and at low levels in noradrenergic neurons. For protocadherin transcripts, several…