Galanin is co-localized with noradrenaline and neuropeptide Y in dog pancreas and celiac ganglion.
To visualize the localization and potential co-localization of noradrenaline and the putative pancreatic sympathetic neurotransmitters, galanin and neuropeptide Y (NPY), immunofluorescent staining for galanin, NPY and tyrosine hydroxylase (TH) was performed on sections of canine pancreas and celiac ganglion. In the pancreas, galanin-immuno-fluorescent nerve fibers were confirmed as densely and preferentially innervating the islets, whereas numerous NPY-positive nerve fibers were found in the exocrine parenchyma, the surrounding of the blood vessels and within the islets. Double-staining for the peptides and TH indicated that most galanin-positive nerve fibers were adrenergic, most NPY-positive nerve fibers were adrenergic, and many islet nerves contained both galanin and NPY, although some galanin-positive nerve fibers appeared to lack NPY. In the celiac ganglion, virtually all cell bodies were positive for both galanin and TH; a large subpopulation of these cells were also positive for NPY. Radioimmunoassay (RIA) of galanin in extracts of dog celiac ganglion revealed a very high content (256 +/- 33 pmol/g wet weight) of galanin-like immunoreactivity (GLIR), consistent with the dense staining observed. This GLIR behaved in a similar manner to synthetic porcine galanin in the RIA. In addition, the majority of the GLIR in ganglion extracts co-eluted with the synthetic peptide upon gel filtration, although a minor peak of a larger apparent molecular weight was also observed, observations consistent with the presence of a precursor peptide. These findings suggest that galanin is a sympathetic post-ganglionic neurotransmitter in the canine endocrine pancreas and that NPY might serve a similar function.
Department of Pharmacology, Lund University, Sweden.
B
B
Ahrén
G
G
Böttcher
S
S
Kowalyk
B E
BE
Dunning
F
F
Sundler
G J
GJ
Taborsky
D000818:Animals; D002850:Chromatography, Gel; D004285:Dogs; D019004:Galanin; D005728:Ganglia, Sympathetic / Q000032:analysis / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D009478:Neuropeptide Y / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011863:Radioimmunoassay; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D009478:Neuropeptide Y; D010455:Peptides; D019004:Galanin; D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine