Hypertrophic smooth muscle in the partially obstructed opossum esophagus: Excitability and electrophysiological properties

Abstract Partial obstruction of the opossum esophagus leads to thickening of the circular muscle, hypertrophy of smooth muscle cells, and diminution of the extracellular space. The pharmacological and electrophysiological properties of this hypertrophied muscle were studied. Carbachol produced phasic and tonic contractions of the circular muscle. The EC 50 for tonic contractions was greater for hypertrophied than for normal muscle (21.1 ± 3.9 μmol/L vs. 4.8 ± 2.2 μmol/L; P P P