Cholinergic stimulation with pyridostigmine blunts the cardiac responses to mental stress

Mental stress may induce myocardial ischemia and ventricular arrhythmia in patients with coronary artery disease, and cholinergic stimulation is a pot ential protective mechanism. The purpose of this study was to determine the effect of pyridostigmine bromide (PYR), a reversible cholinesterase inhibi tor, on the cardiac responses to a mental stress challenge. Twelve healthy young volunteers were submitted to a mental stress test (arithmetic test) 2 hours after the oral administration of either placebo or PYR (45 mg) on tw o separate days, following a randomized crossover double-blind protocol. He art rate was reduced after both placebo and PYR (p < 0.05), but the cardiac responses to the mental stress were lower with PYR (p < 0.05): mean RR int erval (mean +/- SE) - placebo: 730 +/- 19 msec; PYR: 769 +/- 21 msec; Peak systolic pressure - placebo: 129 +/- 4 mmHg; PYR: 124 +/- 3 mmHg; Peak dias tolic pressure placebo: 92 +/- 3 mmHg; PYR: 89 +/- 4 mmHg; Mean rate-pressu re product - placebo: 10,496 +/- 412 bpm x mmHg; PYR: 3,746 +/- 383 bpm x m mHg. In conclusion, 45 mg of pyridostigmine blunted the presser and chronot ropic responses to mental stress in healthy young subjects.