Anatomical Organization of Urocortin 3-Synthesizing Neurons and Immunoreactive Terminals in the Central Nervous System of Non-Human Primates [Sapajus spp.]

Urocortin 3 (UCN3) is a neuropeptide member of the corticotropin-releasing factor (CRF) peptide family that acts as a selective endogenous ligand for the CRF, subtype 2 (CRF2) receptor. Immunohistochemistry and in situ hybridization data from rodents revealed UCN3-containing neurons in discrete regions of the central nervous system (CNS), such as the medial preoptic nucleus, the rostral perifornical area (PFA), the medial nucleus of the amygdala and the superior paraolivary nucleus. UCN3-immunoreactive (UCN3-ir) terminals are distributed throughout regions that mostly overlap with regions of CRF2 messenger RNA (mRNA) expression. Currently, no similar mapping exists for non-human primates. To better understand the role of this neuropeptide, we aimed to study the UCN3 distribution in the brains of New World monkeys of the Sapajus genus. To this end, we analyzed the gene and peptide sequences in these animals and performed immunohistochemistry and in situ hybridization to identify UCN3 synthesis sites and to determine the distribution of UCN3-ir terminals. The sequencing of the Sapajus spp. UCN3-coding gene revealed 88% and 65% identity to the human and rat counterparts, respectively. Additionally, using a probe generated from monkey cDNA and an antiserum raised against human UCN3, we found that labeled cells are mainly located in the hypothalamic and limbic regions. UCN3-ir axons and terminals are primarily distributed in the ventromedial hypothalamic nucleus (VMH) and the lateral septal nucleus (LS). Our results demonstrate that UCN3-producing neurons in the CNS of monkeys are phylogenetically conserved compared to those of the rodent brain, that the distribution of fibers agrees with the distribution of CRF2 in other primates and that there is anatomical evidence for the participation of UCN3 in neuroendocrine control in primates

The proliferative effect of synthetic N-POMC(1-28) peptides in rat adrenal cortex: A possible role for cyclin E

Modified synthetic N-POMC(1-28) without disulfide bridges has been shown to act as an adrenal mitogen. Cyclins and their inhibitors are the major cell cycle controls, but in the adrenal cortex the effect of ACTH and N-POMC on the expression of these proteins remains unclear. In this work, we evaluate the effect of different synthetic N-POMC peptides on the S-phase of the cell cycle. In addition, we examine the cyclin E expression in rat adrenal cortex. Rats treated with dexamethasone were injected with ACTH and/or synthetic modified N-POMC and/or synthetic N-POMC with disulfide bridges. DNA synthesis was determined by BrdU incorporation and protein expression was analyzed by immunoblotting and immunohistochemistry. The results showed that similarly to modified N-POMC without disulfide bridges, administration of synthetic N-POMC with disulfide bridges and the combination of ACTH and N-POMC promoted an increase of BrdU-positive nuclei in adrenal cortex. However, the proliferative effect of N-POMC was comparable to that of ACTH only in the zona glomerulosa. An increase in cyclin E expression was observed 6 h after N-POMC treatment in the outer fraction of the adrenal cortex, in agreement with immunohistochemical findings in the zona glomerulosa. In summary, the effect of synthetic N-POMC with disulfide bridges was similar to modified synthetic N-POMC, increasing proliferation in the adrenal cortex, confirming previous evidence that disulfide bridges are not essential to the N-POMC mitogenic effect. Moreover, cyclin E appears to be involved in the N-POMC- and ACTH-stimulated proliferation in the zona glomerulosa of the adrenal cortex. (C) 2010 Elsevier Ireland Ltd. All rights reserved