[Cholinoreception in Ascaris suum (Nematoda) ascarids and the liver fluke Fasciola hepatica (Trematoda)].

Homogenates of synaptically rich structures of the body (the anterior end of A. suum and F. hepatica, as well as narrow strips of the anterior part of A. suum with median nerves and innervation processes of muscle cells) have been tested for the presence of acetylcholine receptor protein (AchR). Strips of the A. suum muscle tissue with low content of synaptic structures served as a control. AchR was detected by the decrease in the optic density at 260 nm and by the decrease in the reactivity of AchR SH-groups in the presence of Ach. Using both methods, AchR was found in water-soluble fraction of tissue homogenates rich in synaptic structures. No AchR was detected in tissues which do not contain synpatic structures. The data obtained are discussed in relation to the function of Ach as a mediator in helminths.