Electrical activity of intestine recorded with pressure electrode

¹ Department of Physiology, University of Illinois, Urbana, Illinois

The effects of certain autonomic and metabolic drugs on the electrical activity of the small intestine have been investigated, using the pressure electrode. Epinephrine inhibits spike activity and increases the membrane potential, without apparently altering the size of the slow waves. Acetylcholine has the reverse effect. The hyperpolarization produced by epinephrine is followed by a gradual depolarization which exceeds that of the membrane prior to its addition; this is not accompanied by the reappearance of spike activity. Large concentrations of epinephrine produce a waxing and waning of the amplitude of the slow waves. During inhibition by dinitrophenol, both acetylcholine and epinephrine can initiate slow wave activity. An explanation of naturally occurring waxing and waning is suggested, together with a mechanism relating the activity of the two muscle layers during normal intestinal motility.