E. Tagaya et al., ERYTHROMYCIN INHIBITS CHOLINERGIC NEUROEFFECTOR TRANSMISSION IN CANINE AIRWAY SMOOTH-MUSCLE, Research communications in molecular pathology and pharmacology, 85(2), 1994, pp. 181-192
To elucidate whether macrolide antibiotics affect cholinergic neuro-ef
fector transmission in the airway, we studied canine isolated bronchia
l segments under isometric conditions in vitro. Addition of erythromyc
in (3 x 10(-4) M) attenuated the contractile responses to electrical f
ield stimulation (EFS), so that the stimulus frequency required to pro
duce a half-maximal contraction (ES(50)) increased from 1.3 +/- 0.3 to
5.1 +/- 0.5 Hz p < 0.001). This effect was concentration-dependent an
d not influenced by propranolol, indomethacin, ouabain or mechanical r
emoval of the epithelium. In contrast, contractile responses to acetyl
choline were not altered by erythromycin. These results suggest that e
rythromycin may inhibit neuro-effector transmission in the airway chol
inergic motor pathway, probably involving the reduction of exocytotic
release of acetylcholine from the nerve terminals.