抄録
It is well known that cigarette smoking has diverse effects not only on the airway system but also on the pulmonary circulation system. The acute effects of cigarettes are induced mainly by nicotine, the main alkaloid in tobacco. The present investigation was conducted to explore the acute effects of nicotine on canine airway, pulmonary circulation and systemic circulation. We also measured the serum histamine and serotonin levels in order to evaluate the secondary effects of nicotine.
Twelve dogs, weighing between 18 and 25kg, were anesthetized with intravenous administration of 25mg/kg of sodium pentobarbital. The left hemithorax was opened under artificial respiration and tracheal pressure (Ptr) was measured. Catheters were inserted into the pulmonary artery trunk, left atrium and descending aorta. The pulmonary artery pressure (Ppa), left atrium pressure (Pla) and systemic artery pressure (Psyst) were measured. Drugs were injected into the left pulmonary artery through a polyethylene catheter. Ten dogs with closed chest were injected with 1mg of nicotine intravenously, and venous-blood samples were collected once before nicotine injection and 4-5 times after nicotine injection. Serum histamine and serotonin levels were measured, respectively.
1) Ptr increased following injection of nicotine into the left pulmonary artery.
2) Ppa and Psyst increased dose-dependently following injection of nicotine into the left pulmonary artery.
3) Serum histamine level was increased 20 minutes after the intravenous injection of 1mg of nicotine, and remained at a high level for over 60 minutes.
4) Serum serotonin level was decreased significantly 30 seconds and 2 minutes after the intravenous injection of nicotine.
