INVESTIGATION OF THE MODE OF ACTION OF NEMATODE NEUROPEPTIDES

The neuropeptide AF2 has a complex set of actions on the dorsal muscle strip of Ascaris suum, including a potentiation of the acetylcholine- stimulated muscle contraction. Caffeine at 100 mu M and 5 mM inhibited this potentiation, as did 100 mu M theophylline in two out of six stu dies. The cyclic-AMP-potentiating compounds IBMX, dibutyryl cAMP and f orskolin had no effect on the AF2-induced potentiation of the acetylch oline-stimulated muscle contraction. These preliminary data suggest th at the potentiating action of AF2 is not mediated by a cAMP pathway.