Effect of age, gender, rat strain, and dietary restriction, on norepinephrine release from cardiac synaptosomes.

The purpose of the present study was to determine if dietary restriction affected NE release from cardiac synaptosomes obtained from old male F344 rats. Female F344 rats and male and female B/N rats were also examined to determine if age-related changes in norepinephrine (NE) release capacity in the heart are strain- and/or gender-specific. F344 and Brown-Norway (B/N) rats were examined at 6, 12, and 24 months; B/N rats were also examined at 28-30 months. K(+)-induced NE release significantly declined with age in male F344 and B/N rats; this decline was attenuated in female rats and in dietary restricted rats, especially at 24 months. The present study demonstrates that aging reduces the capacity of cardiac adrenergic nerve terminals to release NE, this age-related change is not strain specific, and that dietary restriction and gender alter the extent of this change with age.