Ageing and the Diurnal Expression of mRNAs for Vasoactive Intestinal Peptide and for the VPAC2 and PAC1 Receptors in the Suprachiasmatic Nucleus of Male Rats

Sep 4, 2004Journal of neuroendocrinology

Age-related changes in daily patterns of messenger RNA for a blood vessel regulator and its receptors in the brain's daily rhythm center of male rats

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Ageing reduces VIP mRNA levels and eliminates diurnal expression within the suprachiasmatic nucleus in male rats.

Ageing alters circadian rhythmicity, leading to reduced rhythm amplitude and changes in period length.
There is a loss of diurnal rhythmicity in VIP mRNA expression in aged male rats compared to younger counterparts.
VPAC2 receptor mRNA shows a diurnal rhythm in both age groups, but levels are lower in aged rats.
No significant differences in PAC1 receptor mRNA expression were observed between young and aged rats.

AI simplified

Ageing alters fundamental aspects of circadian rhythmicity in mammals; the effects include reduced rhythm amplitude and alterations in period length and in entrainment to the light/dark cycle. Such changes may reflect disruptions in cellular function within the suprachiasmatic nucleus (SCN), the site of the predominant circadian pacemaker. In the SCN, vasoactive intestinal peptide (VIP)-synthesizing neurones receive various inputs, including retinohypothalamic projections containing pituitary adenylate cyclase activating peptide (PACAP). SCN VIP cells establish connections with local neurones and send efferents beyond the nucleus. Considerable evidence implicates VIP and PACAP in circadian rhythm maintenance and/or entrainment to photic Zeitgebers. These actions involve members of a distinct family of receptors; mRNAs for two such receptors, VPAC2 and PAC1, are present in the SCN. This study used isotopic in situ hybridization to examine the effects of ageing on expression of mRNAs for VIP, VPAC2 and PAC1 in the SCN of male rats under a 12 : 12 h light/dark cycle. Analysis of film autoradiographs from young adult (2-3 months) or aged (19-20 months) rats, at eight time points across the light/dark cycle, showed loss of diurnal rhythmicity and reduced levels for VIP mRNA in the aged group. A diurnal rhythm of VPAC2 receptor mRNA was present in both groups, but its levels were reduced in the aged rats. There were no differences between the two groups for PAC1 receptor mRNA expression. The present results indicate that ageing reduces VIP and VPAC2 receptor mRNA and eliminates diurnal expression of VIP mRNA within the SCN of aged male rats.

Full Text

Full text is available at the source.

View full text ↗

Ageing and the Diurnal Expression of mRNAs for Vasoactive Intestinal Peptide and for the VPAC2 and PAC1 Receptors in the Suprachiasmatic Nucleus of Male Rats

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief