Induction of c-fos Messenger Ribonucleic Acid in Neuropeptide Y and Growth Hormone (GH)-Releasing Factor Neurons in the Rat Arcuate Nucleus Following …

SL Dickson, SM Luckman - Endocrinology, 1997 - academic.oup.com
SL Dickson, SM Luckman
Endocrinology, 1997academic.oup.com
In this study we investigated the neurochemical identity of the arcuate cells activated
following GH-releasing peptide-6 (GHRP-6) injection by comparing, on consecutive
sections, the distribution c-fos messenger RNA (mRNA) with that of mRNAs for peptides
synthesized in arcuate cells, including neuropeptide Y (NPY), GH-releasing factor (GRF),
tyrosine hydroxylase, POMC, and somatostatin. Rats bearing chronically implanted jugular
catheters were injected with either 50 μg GHRP-6 or vehicle. Thirty minutes later they were …
Abstract
In this study we investigated the neurochemical identity of the arcuate cells activated following GH-releasing peptide-6 (GHRP-6) injection by comparing, on consecutive sections, the distribution c-fos messenger RNA (mRNA) with that of mRNAs for peptides synthesized in arcuate cells, including neuropeptide Y (NPY), GH-releasing factor (GRF), tyrosine hydroxylase, POMC, and somatostatin. Rats bearing chronically implanted jugular catheters were injected with either 50 μg GHRP-6 or vehicle. Thirty minutes later they were terminally anesthetized and perfused with fixative. Paraffin-embedded sections of 7 μm thickness were processed using in situ hybridization for either c-fos mRNA or mRNAs for the neurochemical markers. In GHRP-6-treated rats the mean (± sem) number of cells expressing c-fos mRNA in the arcuate nucleus (23 ± 2 cells/section per rat; n = 5) was significantly higher than for vehicle-treated controls (2 ± 1 cells/section per rat; n = 5; P < 0.001, Mann-Whitney U test). Superimposed camera lucida maps indicated that, in GHRP-6-injected rats, neurochemically identifiable cells expressing c-fos mRNA also express NPY mRNA (51 ± 4%), GRF mRNA (23 ± 1%) tyrosine hydroxylase mRNA (11 ± 3%), POMC mRNA (11 ± 2%), or somatostatin mRNA (4 ± 1%). Thus, the majority of cells expressing c-fos mRNA following GHRP-6 injection are NPY and GRF-containing cells.
Oxford University Press