Spontaneous electromechanical activity in the rat duodenumin vitro

Isolated rat duodenum shows spontaneous mechanical and electrical activities. Mechanical activity consists in changes both in endoluminal pressure and in isometric tension. Electrical activity is characterized by slow waves with superimposed bursts. This spontaneous activity is tetrodotoxin (TTX) resistant and therefore it is myogenic in origin. Indeed, TTX pretreatment, even in the presence of atropine and guanethidine, caused an increase in amplitude and in frequency of the electrical and mechanical activities. This finding indicates the presence of tonically active inhibitory intramural non adrenergic, non cholinergic (NANC) nerves. Duodenal longitudinal strips showed a spontaneous mecha…