Sympathetic cholinergic target innervation requires GDNF family receptor GFR alpha 2.
Many cholinergic parasympathetic and enteric neurons require neurturin signaling through GDNF family receptor GFRalpha2 for target innervation. Since a distinct minority of sympathetic neurons are cholinergic, we examined whether GFRalpha2 is important for their development. We detected GFRalpha2 in neonatal sympathetic cholinergic neurons and neurturin mRNA in their target tissues, sweat glands in footpads, and periosteum. Lack of GFRalpha2 in mice did not affect the number of sympathetic cholinergic neurons, but their soma size was decreased in comparison to wild types. In adult and in 3-week-old GFRalpha2 knockout mice, the density of sympathetic cholinergic innervation was reduced by 50-70% in the sweat glands, and was completely absent in the periosteum. Sympathetic noradrenergic innervation of blood vessels in the footpads was unchanged. The density of sympathetic axons in sweat glands was unaffected at postnatal day P4 reflecting successful growth into the target area. Our results indicate that the cholinergic subpopulation of sympathetic neurons requires GFRalpha2 signaling for soma size and for growth or maintenance of target innervation. Thus, neurturin may be a general target-derived innervation factor for postganglionic cholinergic neurons in all parts of the autonomic nervous system.
Hiltunen
Päivi H
PH
Neuroscience Center, 00014 University of Helsinki, Finland.
Airaksinen
Matti S
MS
D000320:Adrenergic Fibers / Q000502:physiology*; D000818:Animals; D048429:Cell Size / Q000235:genetics; D002799:Cholinergic Fibers / Q000378:metabolism*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010521:Periosteum / Q000166:cytology / Q000294:innervation / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000172:deficiency* / Q000235:genetics* / Q000502:physiology; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000172:deficiency* / Q000235:genetics* / Q000502:physiology; D013545:Sweat Glands / Q000166:cytology / Q000294:innervation / Q000378:metabolism
C494991:Gfra2 protein, mouse; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases