A comparison of respiratory (J) sensations induced by intravenous lobeline injectionand produced by exercise in subjects with coronary artery disease

A small dose of intravenous bolus injection of lobeline (LB) gives rise to a range of sensations in the upper respiratory tract (named J sensations) including dryness, swelling, burning, suffocation in the upper respiratory tract, and dry cough. We were interested in investigating: a) whether people with coronary artery disease (CAD) feel the same kind of sensations with LB as those of healthy subjects, b) we also attempted to compare these sensations with those felt when they were exercising moderately, and c) finally, a similar comparison, undertaken in healthy subjects, allowed us to examine the origin of exercise-related sensations experienced by subjects with CAD. J sensations were evoked by threshold doses of LB in 10 CAD patients and 10 healthy subjects as control. These sensations were then experienced in treadmill exercise tolerance testing (Bruce Protocol) and compared. Diversity and incidence of J sensations felt with the above protocol were ignificantly higher amongst CAD patients than the control subjects. CAD patients usually reported experiencing more than one kind of J sensations, when exercising. It is worth mentioning that dry cough was present in 30% of CAD patients while exercising, but was absent in the healthy subjects. The notable similarity between J sensations evoked by threshold doses of LB and those felt while exercising, as reported by CAD patients, points to the common origin of these sensations in the two conditions. The foreseeable conclusion is that the similarity of J sensations encountered while exercising with those of the LB-induced ones in CAD patients points to the fact that the origin of these exercise-induced sensations is the stimulation of juxta-pulmonary capillary (J) receptors by transient increment in interstitial volume and/or increase in pulmonary blood flow.