Deltamethrin infusion into different sites in the neuraxis of freely-moving rats

A comparison of signs induced by deltamethrin infusion at 3 sites within the neuraxis was made in freely-moving rats. Cannulae were placed prior to experiment into either lateral ventricle, cisterna magna or spinal subarachnoid space and animals allowed to recover. Deltamethrin was active at all levels of the neuraxis in a dose dependent manner. All signs induced by intraperitoneal deltamethrin administration, except profuse salivation and choreoathetosis, were generated by direct infusion of the compound into the CNS. In addition other signs developed which cannot be observed following systemic administration. They seemed to reflect a local disturbance in function around each injection site. With regard to the major symptom of choreoathetosis associated with systemic deltamethrin administration, the results suggest that for such a complex response to develop, a more global activation at many levels of the neuraxis (and possibly in the periphery) is required.