Pharmacologic Effects of Nicotine on Isolated Aorta, Trachea and Lung Function of Rat

Nicotine is one of the most important substances in cigar and the cigarrete Smoke. Smoking may cause an increase in blood pressure and affecting respiratory functions. In this study the effect of nicotine on isolated aorta and trachea of rat and also it's effect on the bronchial resistance, was investigated. In the in vitro experiments, trachca or aorta was removed and placed in an isolated tissue organ bath containing Krebs Henseleit solution at pH 7.2-7.4 at 37°C and aerated with 95% 02 and 5% CO2. Epineprine (for aorta) and acetylcholine (for trachea) were used as Standard Stimulating agents. They elicit a dose dependent contracture in those t issues. Dose-response curve was established for each drug. Then different concentrations of nicotine solution ( 10 to 10 M) was tested on either aorta or trachea. Results showed that nicotine with such concentrations can not elicit contraction in isolated rat aorta and trachea. In the in vivo experiments, different doses of drugs were directly nebulized in the rat trachea and their effects on the bronchial resistance were measured. Barium chloride (BACl2) was used as standard stimulating agent and changes in bronchial resistance was recorded. Epinephrine was used to reverse the bronchospasm induced by BaCb. Then different concentrations of nicotine solution (10 to 10 M) was nebulized. According to the results of this study nicotine with these concentrations had no bronchoconstriction effect in rat. Therfore it can be conclouded that nicotine alone has no direct effect on isolated bonchia, aorta or bronchial resistance. However its adverse effect on human health may be due to other adjuant ingredients in cigarrete smoke.