RT Journal Article
SR Electronic
T1 Neurochemical Characterization and Sexual Dimorphism of Projections from the Brain to Abdominal and Subcutaneous White Adipose Tissue in the Rat
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 15913
OP 15921
DO 10.1523/JNEUROSCI.2591-12.2012
VO 32
IS 45
A1 Elaine S. Adler
A1 Jacob H. Hollis
A1 Iain J. Clarke
A1 David R. Grattan
A1 Brian J. Oldfield
YR 2012
UL http://www.jneurosci.org/content/32/45/15913.abstract
AB Retroperitoneal white adipose tissue (rWAT) and subcutaneous (inguinal) white adipose tissue (iWAT) are both innervated and regulated by sympathetic efferents, but the distribution and identity of the cells in the brain that regulate sympathetic outflow are poorly characterized. Our aim was to use two isogenic strains of a neurotropic virus (pseudorabies, Bartha) tagged with either green or red fluorescent reporters to identify cells in the brain that project to rWAT and/or iWAT. These viruses were injected into separate WAT depots in male and female Sprague Dawley rats. Retrogradely labeled neurons in the CNS were characterized by immunohistochemistry and PCR. For the latter, laser capture of individual virally labeled neurons was used. All virally labeled brain regions contained neurons projecting to either and both WAT depots. Neurons to abdominal fat were the most abundant in males, whereas females contained a greater proportion of neurons to subcutaneous via private lines and collateral branches. Retrogradely labeled neurons directed to WAT expressed estrogen receptor-α (ERα), and fewer neurons to subcutaneous WAT expressed ERα in males. Regardless of sex, projections from the arcuate nucleus were predominantly from pro-opiomelanocortin cells, with a notable lack of projections from agouti-related protein-expressing neurons. Within the lateral hypothalamus, neurons directed to rWAT and iWAT expressed orexin and melanin-concentrating hormone (MCH), but male rats had a predominance of MCH directed to iWAT. In conclusion, the neurochemical substrates that project through polysynaptic pathways to iWAT and rWAT are different in male and female rats, suggesting that metabolic regulation of rWAT and iWAT is sexually dimorphic.