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Time and dose effect of transdermal nicotine on endothelial function
V M Miller1, W D Clouse, B H Tonnessen
1Departments of Surgery, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA. miller.virginia@mayo.edu
American Journal of Physiology. Heart and Circulatory Physiology
|September 29, 2000
Summary
Nicotine patches impact blood vessel function over time. Long-term use, particularly at higher doses, may reduce endothelium-dependent relaxations, affecting nitric oxide bioavailability.
Area of Science:
- Cardiovascular Science
- Pharmacology
Background:
- Nicotine patches are common aids for smoking cessation.
- The effects of nicotine therapy on vascular function require further investigation.
Purpose of the Study:
- To investigate the impact of nicotine patch therapy duration and dosage on endothelium-dependent relaxations.
- To explore the relationship between nicotine exposure, nitric oxide products, and vascular responses.
Main Methods:
- Dogs received nicotine patches at varying doses (11, 22, 44 mg/day) for 2 and 5 weeks.
- Measurements included circulating nicotine, nitric oxide metabolites (NOx), and nitric oxide synthase (NOS) activity and mRNA in aortic endothelial cells.
- Isometric force measurements assessed endothelium-dependent relaxations in coronary arteries.
Main Results:
- Circulating nicotine levels correlated with patch dosage.
- After 5 weeks of 22 mg/day nicotine treatment, NOx levels decreased while NOS activity increased.
- Endothelium-dependent relaxations were impaired only after 5 weeks of 22 mg/day nicotine treatment.
Conclusions:
- Nicotine patch therapy exhibits a time- and dose-dependent effect on endothelium-dependent responses.
- These effects may be linked to alterations in nitric oxide bioavailability.
- The complex relationship between nicotine dose, duration, and vascular response may explain varied research findings.