[The vulnerability of peripheral nerves and the somatic toxin linkage in tick paralysis of chickens, caused by Argas (Persicargas) walkerae (author's transl)].

Investigations on the impulse propagation and the pattern of amplitudes of toxically by Argas (Persicargas) walkerae larvae impaired peripheral nerves were carried out under oxygen saturated and anoxic conditions. It was demonstrated, that the maximum nerve conduction velocities of the isolated N. ischiadicus were slightly lowered in the first carbogenic and anoxic phase, in comparison with normal nerves. After the second incubation the conduction velocities were, however, almost the same or even higher. The survival times of the nerves after anoxic exposure, which were determined by the temporal persistence of the potentials, revealed that this neurophysiological parameter always resulted in a higher value for the damaged nerves after every two anoxic phases. The diseased nerves therefore tolerate anoxia longer and better than do healthy nerves in respect to their excitability and in their function of impulse propagation. From these in vitro investigations it is concluded that the noxious substance responsible for the paralysis is not cell-bound, but circulates humorally. The toxin possesses membranophilic properties, but its somatic linkage is very labile.