Cyclic nucleotide changes and contractility in the rat anococcygeus muscle.

The rat anococcygeus muscle can be activated by three different agonists, NA, ACh and KCl, each of these displaying a different degree of pharmacomechanical coupling. Investigation of cyclic nucleotide changes in the muscles when activated showed that changes in cAMP/cGMP ratio parallel changes in contractility. However, the cyclic nucleotide changes seem incidental to the process of contraction, rather than causally related to it.