Melatonin attenuates thiocyanate-induced vasoconstriction in aortic rings

Area of Science:

• Cardiovascular Physiology
• Pharmacology
• Toxicology

Background:

• Cigarette smoking increases arterial blood pressure and atherosclerotic disease progression.
• Thiocyanate anions (SCN⁻) in cigarette smoke correlate with consumption and may accelerate atherosclerosis.
• Melatonin, an antioxidant, is investigated for potential atheroprotective effects.

Purpose of the Study:

• To quantify the thiocyanate-induced vasomotor response in rat aortic tissue.
• To examine melatonin's potential to modulate thiocyanate-induced vasoreactivity.

Main Methods:

• Rat aortic rings were exposed to varying concentrations of thiocyanate.
• Vasomotor responses were measured in organ baths.
• Melatonin (60-360 pM) was administered to assess its effect on vasoreactivity.

Main Results:

• Thiocyanate caused concentration-dependent vasoconstriction in aortic rings.
• Preincubation with 360 pM melatonin reduced thiocyanate's effect by 56.5% (P < 0.0001).
• Melatonin (360 pM) induced 10.9% relaxation at 80 mM norepinephrine, which was reduced at higher norepinephrine concentrations.

Conclusions:

• Thiocyanate induces dose-dependent vasoconstriction in aortic vessels.
• Melatonin significantly attenuates thiocyanate-induced vasoconstriction.
• Melatonin demonstrates potential as a therapeutic agent against smoking-related vascular dysfunction.