The spontaneous electrical and mechanical activity of the longitudinal smooth muscle of the rabbit duodenum and its modification by drugs and temperature changes

Abstract

The electrical and mechanical activity of strips of longitudinal smooth muscle from the rabbit duodenum was recorded using the sucrose gap method. The muscle exhibited rhythmic tension changes each of which was associated with a slow potential wave of electric depolarization surmounted by a burst of spike activity (a multispike complex). Cooling the tissue reduced the frequency of tension waves and multispike complexes. Catecholamines produced a reduction in the amplitude of tension waves. This was associated with hyperpolarization and decreased spike activity. Slow wave frequency and amplitude were unaffected. Acetylcholine, methacholine and histamine produced tension wave fusion associated with depolarization and increased spike activity.