Age-Associated Reduction in Pineal Beta-Adrenergic Receptor Density Is Prevented by Life-Long Food Restriction in Rats

Abstract

At 28 months of age (old rats), male Fisher 344 rats which had been fed 40% of the ad libitum food intake since they were 6 months old, had a similar β-adrenergic receptor density (B_max) in their pineal gland as young, 3-month-old rats. In contrast, old rats which had been fed ad libitum for the same period had approximately 50% of the B_max value compared to that of young rats. The β-receptor density of cerebral cortical tissue and the β-receptor affinity (K_d) of both the cortex and the pineal gland did not decline with age and was not affected by food restriction. The reduction in pineal β-receptor density with age may be causally related to the concurrent age-associated decline in pineal production of melatonin.

Pineal Calcification, Melatonin Production, Aging, Associated Health Consequences and Rejuvenation of the Pineal Gland

“…The reasons for this may be two-fold. Melatonin synthetic capacity is dampened during aging due to the reduced density of β-adrenergic receptors in the pineal gland [ 215 , 216 ] and the downregulation of gene expression or phosphorylation of AANAT / SNAT [ 217 ]. A second reason is the increased consumption of melatonin.…”

Caloric restriction, resveratrol and melatonin: Role of SIRT1 and implications for aging and related-diseases

“…Fisher 344 rats given 60% of the food eaten by control animals retained a melatonin rhythm at 29 months of age that was equivalent to those of much younger animals. Food restriction presumably conserves the melatonin rhythm in part because it prevents the reduction in pineal ␤-adrenergic receptors normally reported in old rats (Henden et al, 1992). The loss of melatonin in the elderly may lead to disorders of circadian rhythms, referred to as chronodisruption (Erren and Reiter, 2009), causing a desynchronization of the various genes resulting in a decrease in overall health (Karasek, 2007;Jung-Hynes et al, 2010).…”

Changes in nocturnal melatonin secretion in perimenopausal women: Correlation with endogenous estrogen concentrations

“…However, Greenberg and Weiss [1978] have demonstrated that the density of the b-adrenergic receptors in the rat pinealocyte membrane declines with age. Henden et al [1992] also demonstrated that although the b-adrenergic receptor affinity for the radioligand was not altered with age, the density of receptors in the pineal gland of 28-month-old male rats was only 50% that of the pineal of young adult males. An age-associated biphasic decline in nocturnal melatonin concentrations postmenopause may be the results of multiple factors.…”