Nicotine Enhances Angina Pectoris-Like Chest Pain and Atrioventricular Blockade Provoked by Intravenous Bolus of Adenosine in Healthy Volunteers

Summary: An attempt was made to study possible interaction between neuromodulation by adenosine and nicotine stimulatory effects. Dose–effect curves were made double blind in 7 nonsmoking, nonsnuffing healthy volunteers (25–49 years) before and during exposition to nicotine roughly corresponding to the nicotine of one cigarette, 2 mg ingested from a chewing gum (800 chews during 20 min). Chest pain was estimated by the Borg CR-10 scale. ECG was followed, and respiration was recorded continuously by spirometry. Maximal tolerable dose of adenosine was 12.7 ±3.0 mg. Chest pain increased dose dependently to 5.7 ± 1.7 units. Nicotine increased the pain response by 20 ± 15%, (p < 0.02). The total time with atrioventricular (AV) block provoked by adenosine increased with nicotine (7 ± 12%, p < 0.03) while increased ventilation provoked by adenosine was unaffected by nicotine. In conclusion, interaction between adenosine and nicotine was demonstrated. Nicotine enhanced both stimulatory (chest pain) and inhibitory actions (AV-block) of adenosine.