ABSTRACT
Different species of parasitic nematode infect man and animals, giving rise to a range of symptoms including reduced growth, diarrhoea, and sometimes death. Some drugs used to treat these infestations interfere selectively with ion-channels in nerves or muscle cells of the nematode. Levamisole opens nicotinic acetylcholine channels in nematode somatic muscle to produce depolarisation and spastic paralysis without an effect on the host. The GABA-agonist, piperazine, and the antibiotic avermectins gate CI channels in nerve or muscle of nematodes to produce paralysis. Quisqualate has an action on an excitatory glutamate channel. All these drugs have a selective effect on nematode parasites; their neuromuscular system is disturbed so that the parasites are no longer capable of maintaining their position in the host. In order to understand the mode of action of the anthelmintics, knowledge of the organisation of nematode neuromuscular transmission is required. The regular use of anthelmintic drugs has brought about selection of anthelmintic-resistant nematodes; the investigation of resistance involves studying the modifications of the control of neuromuscular systems associated with the resistance.
