Abstract
To clarify the mechanisms regulating the function of smooth muscle the relations of changes in metabolism to its function have been examined by several investigators. Adrenaline is known to depress the motility of the intestine and the uterus and it also increases the content of cyclic AMP and the activity of phosphorylase a (1-3). Experiments have shown that on addition of adrenaline the increase in phosphorylase a activity is preceded by the increase in the cyclic AMP level and the decrease in motility (1, 2). Thus, the relation between the content of cyclic AMP and the motility of the intestine seems interesting. This paper reports the effects of cyclic AMP and its derivative on isolated ileum. The hypothesis that cyclic AMP is an intracellular messenger for transmitting information from outside the cell by hormones and neurotransmitters, including catecholamines (4, 5) is discussed on the basis of the results.
