IMR Press / JIN / Volume 20 / Issue 3 / DOI: 10.31083/j.jin2003060
Open Access Original Research
Spinal relay neurons for central control of autonomic pathways in a photoperiodic rodent
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1 Department of Nuclear Medicine, University Medical Center, Johannes Gutenberg-University, 55101 Mainz, Germany
J. Integr. Neurosci. 2021, 20(3), 561–571; https://doi.org/10.31083/j.jin2003060
Submitted: 18 February 2021 | Revised: 4 March 2021 | Accepted: 26 April 2021 | Published: 30 September 2021
Abstract

Location and distribution of spinal sympathetic preganglionic neurons projecting to the superior cervical ganglion were investigated in a rodent model organism for photoperiodic regulation, the Djungarian hamster (Phodopus sungorus). Upon unilateral injection of Fluoro-Gold into the superior cervical ganglia, retrograde neuronal tracing demonstrated labeled neurons ipsilateral to the injection site. They were seen in spinal segments C8 to Th5 of which the segments Th1 to Th3 contained about 98% of the labeled cells. Neurons were found in the spinal cord predominantly in the intermediolateral nucleus pars principalis and pars funicularis. At the same time, the central autonomic area and the intercalated region contained only very few labeled cells. In the intermediolateral nucleus, cells often were arranged in clusters, of which several were seen in each spinal segment. Selected sections were exposed to antibodies directed against arginine-vasopressin, neuronal nitric oxide synthase, neuropeptide Y, neurotensin, oxytocin or substance P. It was found that about two-thirds of sympathetic preganglionic neurons produced the gaseous neuroactive substance nitric oxide and that few contained small amounts of neuropeptide Y. Fibers of putative supraspinal origin immunopositive for either arginine-vasopressin, neuronal nitric oxide synthase, neuropeptide Y, neurotensin, oxytocin or, in particular, substance P were found in the vicinity of labeled sympathetic preganglionic neurons. These results demonstrate the location of relay neurons for autonomic control of cranial and cardial structures and provide further knowledge on neurochemical properties of sympathetic preganglionic neurons and related structures.

Keywords
Arginine-vasopressin
Djungarian hamster
Fluoro-Gold
Neuronal nitric oxide synthase
Neuropeptide tyrosine
Neurotensin
Oxytocin
Phodopus sungorus
Sympathetic preganglionic neurons
Superior cervical ganglion
Spinal Cord
Substance P
Figures
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