CGRP innervation and receptors during aging of male and female hepatic rat portal veins

Effects of aging on proteasomal-ubiquitin system, oxidative stress balance and calcium homeostasis in middle-aged female rat colon

Aging is a multifactorial process, which is considered as a decline over time. It is increasingly clear that there is a gender difference in aging and in the prevalence of age-related diseases as well. We aimed to examine the effects of the aging process in the colonic tissue of female Wistar rats aged 10 weeks (young) and 13 months (middle-aged) at an early stage, according to three main symptoms associated with aging: a decrease in the efficacy of the proteasome and muscle function and an increase in oxidative stress. The aging process was found to cause a significant decrease in ubiquitin C-terminal hydrolase ligase (UCHL-1) and a significant increase in 3-nitrotyrosine (3-NT), total glutathione (GSH), calcium (Ca2+), calcitonin gene-related peptide (CGRP) and superoxide dismutase (SOD) activity in middle-aged animals. In summary, it is suggested that the reduced activity of the proteasomal degradation system may be the result of the diminished expression of the UCHL-1 enzyme and the decreased levels of ubiquitin; furthermore, we found some key targets which may help to better understand the fundamental aging process.

Changes in the distribution of nerve fibers immunoreactive to calcitonin gene-related peptide according to growth and aging in rat molar periodontal ligament

OBJECTIVE

To analyze the age-dependent changes in nerve fibers immunoreactive to calcitonin gene-related peptide (CGRP-ir) in the periodontal ligaments of rats.

MATERIALS AND METHODS

Thirty male Wistar-ST rats were divided into growing groups (5, 9, and 15 weeks of age) and aging groups (6, 12, and 24 months of age) (n = 5 in each group). Eight serial sagittal sections, 5 microm thick, were cut parallel to the distobuccal root of the maxillary right first molar. These tissues were stained with a rabbit monoclonal antibody against CGRP. The observation area was divided into three parts (mesial, apical, and distal) and observed using a light microscope.

RESULTS

CGRP-ir nerve fibers were primarily distributed in the apical periodontal ligament in the growing group, with significantly more fibers than in the aging group.

CONCLUSIONS

CGRP-ir nerve fibers in the periodontal ligament are dense during the growth period and decrease gradually with aging, indicating that CGRP may affect periodontal tissue with growth and aging.

The neuropeptide calcitonin gene-related peptide differently modulates proliferation and differentiation of smooth muscle cells in culture depending on the cell type

Calcitonin gene-related peptide (CGRP) is a neuropeptide present around vasculature very early during development, when smooth muscle cells (SMC) are still proliferating and not yet totally differentiated. We investigated the effects of CGRP on proliferation and differentiation of SMC in culture; 10(-7) M CGRP added in the medium of cultured smooth muscle cells every 2 days did not significantly changed cells growth rate in 1% FCS. At the opposite, this treatment modulated proliferation of cells grown in 10% FCS medium. Two distinct populations of SMC with different growth rates were obtained from our primary cultures. SMC which proliferated slowly in the presence of 10% fetal calf serum (FCS) had growth rates positively influenced by CGRP. The quantity of alpha-smooth actin expressed by these cells was not influenced by the peptide. On the contrary, SMC which proliferated more rapidly in 10% FCS medium had growth rate inhibited by CGRP. In these cells, CGRP significantly reduced the amount of expressed alpha-smooth actin, an index of SMC differentiation. In both cases, the peptide significantly increased the level of mRNA for all the actin genes. In the light of this dual role of CGRP, it can be presumed that this peptide controls smooth muscle cells proliferation and differentiation in vivo and could thus regulate the homeostasis of the vessel wall.