Possible association of decrease of ATP-induced vascular relaxation with reduction of cyclic GMP during aging

Area of Science:

• Cardiovascular Physiology
• Aging Research
• Vascular Biology

Background:

• Adenosine triphosphate (ATP) plays a role in vascular tone regulation.
• Aging is associated with altered cardiovascular function.
• The impact of aging on ATP-mediated vascular responses requires further elucidation.

Purpose of the Study:

• To investigate the effects of aging on ATP-induced relaxation in rat thoracic aorta.
• To determine the role of cyclic guanosine monophosphate (cGMP) in age-related changes.
• To identify potential mechanisms underlying impaired vascular relaxation in aged rats.

Main Methods:

• Assessment of ATP-induced relaxation in rat thoracic aorta from rats of different ages (4, 45, and 105 weeks).
• Measurement of cyclic GMP and cyclic AMP levels in response to ATP.
• Inhibition studies using haemoglobin, methylene blue, and NG-nitro L-arginine, and endothelium removal.

Main Results:

• ATP-induced relaxation was highest in young rats and significantly reduced in older rats (45 and 105 weeks).
• ATP elevated endothelium-dependent cyclic GMP levels, an effect attenuated with age and abolished in 105-week-old rats.
• Cyclic AMP production was unaffected by aging, suggesting a specific role for the cGMP pathway.

Conclusions:

• Aging impairs ATP-induced relaxation of rat thoracic aorta, primarily through reduced cyclic GMP formation.
• The age-related decline in relaxation appears to involve vascular smooth muscle, potentially affecting soluble guanylate cyclase or downstream signaling.
• These findings highlight age-associated alterations in vascular smooth muscle signaling pathways.