TY - JOUR
T1 - Identification of neurons that express ghrelin receptors in autonomic pathways originating from the spinal cord
AU - Furness, John B.
AU - Cho, Hyun Jung
AU - Hunne, Billie
AU - Hirayama, Haruko
AU - Callaghan, Brid P.
AU - Lomax, Alan E.
AU - Brock, James A.
N1 - Funding Information:
This work was supported by a grant from the National Health and Medical Research Council of Australia (grant no. 1005811). A.E.L. was supported by a New Investigator Award from the Canadian Institutes of Health Research. The study utilised resources of the Australian Phenomics Network. J.B.Furness(*).H.-J.Cho.B.Hunne.H.Hirayama. B. P. Callaghan.J. A. Brock Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia e-mail: j.furness@unimelb.edu.au
PY - 2012/6
Y1 - 2012/6
N2 - Functional studies have shown that subsets of autonomic preganglionic neurons respond to ghrelin and ghrelin mimetics and in situ hybridisation has revealed receptor gene expression in the cell bodies of some preganglionic neurons. Our present goal has been to determine which preganglionic neurons express ghrelin receptors by using mice expressing enhanced green fluorescent protein (EGFP) under the control of the promoter for the ghrelin receptor (also called growth hormone secretagogue receptor). The retrograde tracer Fast Blue was injected into target organs of reporter mice under anaesthesia to identify specific functional subsets of postganglionic sympathetic neurons. Cryo-sections were immunohistochemically stained by using anti-EGFP and antibodies to neuronal markers. EGFP was detected in nerve terminal varicosities in all sympathetic chain, prevertebral and pelvic ganglia and in the adrenal medulla. Non-varicose fibres associated with the ganglia were also immunoreactive. No postganglionic cell bodies contained EGFP. In sympathetic chain ganglia, most neurons were surrounded by EGFP-positive terminals. In the stellate ganglion, neurons with choline acetyltransferase immunoreactivity, some being sudomotor neurons, lacked surrounding ghrelin-receptor-expressing terminals, although these terminals were found around other neurons. In the superior cervical ganglion, the ghrelin receptor terminals innervated subgroups of neurons including neuropeptide Y (NPY)-immunoreactive neurons that projected to the anterior chamber of the eye. However, large NPY-negative neurons projecting to the acini of the submaxillary gland were not innervated by EGFP-positive varicosities. In the celiacosuperior mesenteric ganglion, almost all neurons were surrounded by positive terminals but the VIP-immunoreactive terminals of intestinofugal neurons were EGFP-negative. The pelvic ganglia contained groups of neurons without ghrelin receptor terminal innervation and other groups with positive terminals around them. Ghrelin receptors are therefore expressed by subgroups of preganglionic neurons, including those of vasoconstrictor pathways and of pathways controlling gut function, but are absent from some other neurons, including those innervating sweat glands and the secretomotor neurons that supply the submaxillary salivary glands.
AB - Functional studies have shown that subsets of autonomic preganglionic neurons respond to ghrelin and ghrelin mimetics and in situ hybridisation has revealed receptor gene expression in the cell bodies of some preganglionic neurons. Our present goal has been to determine which preganglionic neurons express ghrelin receptors by using mice expressing enhanced green fluorescent protein (EGFP) under the control of the promoter for the ghrelin receptor (also called growth hormone secretagogue receptor). The retrograde tracer Fast Blue was injected into target organs of reporter mice under anaesthesia to identify specific functional subsets of postganglionic sympathetic neurons. Cryo-sections were immunohistochemically stained by using anti-EGFP and antibodies to neuronal markers. EGFP was detected in nerve terminal varicosities in all sympathetic chain, prevertebral and pelvic ganglia and in the adrenal medulla. Non-varicose fibres associated with the ganglia were also immunoreactive. No postganglionic cell bodies contained EGFP. In sympathetic chain ganglia, most neurons were surrounded by EGFP-positive terminals. In the stellate ganglion, neurons with choline acetyltransferase immunoreactivity, some being sudomotor neurons, lacked surrounding ghrelin-receptor-expressing terminals, although these terminals were found around other neurons. In the superior cervical ganglion, the ghrelin receptor terminals innervated subgroups of neurons including neuropeptide Y (NPY)-immunoreactive neurons that projected to the anterior chamber of the eye. However, large NPY-negative neurons projecting to the acini of the submaxillary gland were not innervated by EGFP-positive varicosities. In the celiacosuperior mesenteric ganglion, almost all neurons were surrounded by positive terminals but the VIP-immunoreactive terminals of intestinofugal neurons were EGFP-negative. The pelvic ganglia contained groups of neurons without ghrelin receptor terminal innervation and other groups with positive terminals around them. Ghrelin receptors are therefore expressed by subgroups of preganglionic neurons, including those of vasoconstrictor pathways and of pathways controlling gut function, but are absent from some other neurons, including those innervating sweat glands and the secretomotor neurons that supply the submaxillary salivary glands.
KW - Autonomic ganglia
KW - Ghrelin
KW - Immunohistochemistry
KW - Mouse
KW - Preganglionic neurons
KW - Retrograde tracing
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U2 - 10.1007/s00441-012-1405-9
DO - 10.1007/s00441-012-1405-9
M3 - Article
C2 - 22538519
AN - SCOPUS:84866331834
SN - 0302-766X
VL - 348
SP - 397
EP - 405
JO - Cell and Tissue Research
JF - Cell and Tissue Research
IS - 3
ER -