title: Distribution and chemical coding of sensory neurons innervating the skin of the porcine hindlimb.
abstract: The aim of the present study was to establish the origin and chemical phenotyping of neurons involved in skin innervation of the porcine hind leg. The dorsal root ganglia (DRGs) of the lumbar (L4-L6) and sacral (S1-S3) spinal nerves were visualized using the fluorescent tracer Fast Blue (FB). The morphometric analysis of FB-positive (FB+)neurons showed that in the L4, L5, S1and S2DRGs, the small-sized perikarya constituted the major population, whereas in the L6and S3DRGs the medium-sized cells made up the major population. In all these ganglia, large-sized FB+ perikarya constituted only a small percentage of all FB+ neurons. Immunohistochemistry revealed that small- and medium-sized FB+ perikarya contained sensory markers such as: substance P (SP), calcitonin gene related peptide (CGRP) and galanin (GAL); as well as various other factors such as somatostatin (SOM), calbindin-D28k (CB), pituitary adenylate cyclase-activating polypeptide (PACAP) and neuronal nitric oxide synthase (nNOS). Meanwhile large-sized FB+ perikarya usually expressed SP, CGRP or PACAP. In the lumbar DRGs, some large cells also contained SOM and CB. Double-labeling immunohistochemistry showed that SP-positive neurons co-expressed CGRP, GAL or PACAP; while PACAP-positive cells co-expressed GAL or nNOS. Neurons stained for SOM were also immunoreactive for CB or GAL, while neurons stained for nNOS were also immunoreactive for GAL. In conclusion, the present data has indicated that the distribution and chemical phenotyping of the porcine skin-projecting neurons are different within DRGs of the lumbar (forming a femoral nerve) and sacral (forming a sciatic nerve) spinal nerves.
authors.affiliation: Department of Human Physiology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, Poland. Electronic address: kozlowska.anna@uwm.edu.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Kozłowska
authors.affiliation: Department of Public Health, Epidemiology and Microbiology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, Poland.
authors.forename: Anita
authors.initials: A
authors.lastname: Mikołajczyk
authors.affiliation: Department of Surgery and Radiology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Adamiak
authors.affiliation: Department of Human Physiology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, Poland.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Majewski
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D005260:Female; D019004:Galanin / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D006614:Hindlimb / Q000294:innervation*; D007150:Immunohistochemistry; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism*; D012867:Skin / Q000294:innervation*; D013373:Substance P / Q000378:metabolism*; D013552:Swine
chemical_list: D013373:Substance P; D019004:Galanin; D015740:Calcitonin Gene-Related Peptide
keywords: Chemical coding; DRG; Gilts; Skin