THE EFFECT OF TEMPERATURE VARIATIONS AND OF CERTAIN DRUGS UPON THE INTESTINAL MOTILITY OF ELASMOBRANCH FISHES

Abstract

A rise of temperature increases the rate of the spontaneous contraction of the spiral intestine and valve, rectum and colon. At any one temperature the upper end of the spiral intestine has the same rate of contraction as the lower end, whereas the upper end of the spiral valve has a higher rate than the lower end. The rectum and colon have no rapid rhythm, but give a single spasmodic contraction every half hour or so.Adrenaline, pilocarpine and acetylcholine stimulate all the above parts, though the effect of pilocarpine on the spiral valve is very indefinite. Atropine has no effect on normal contractions, but counteracts the effect of acetylcholine and pilocarpine.