Disorders of the Nervous System

Author: CARLOS MEDINA SALDIVAR | Email: carlos.medina.s@upch.pe

Carlos Medina Saldivar , Bety Jahaira Guzman Paro , Luis Fernando Pacheco Otalora

1° Neuroscience Research Laboratory, Universidad Andina del Cusco

BACKGROUND: Pentylenetetrazol (PTZ) epilepsy model in rodents has been used for more than 40 years to test new anticonvulsant drugs using the behavioral Racine scale as a reference. However, due to phenotypical differences, this scale is not universally applicable to all rodents and strains. In the present study, we characterized the behavioral evolution of epileptic symptoms in a rat PTZ kindling model in both sexes. METHOD: PTZ saline solution was administered at 70mg/kg i.p. the first day and then 35 mg/kg every other day for 5 weeks to 1-month-old Sprague-Dawley rats of both sexes. The activity was videorecorded for 30 minutes and the behavior test was evaluated. For the histological study, animals were perfused 1, 2, and 3 months after the last PTZ administration and brains were collected. RESULTS: Ten behaviors were described: catalepsy, facial jerk, neck jerk (agitation or assent), forelimb jerk, clonic seizures or tonic seizures (sitting or lying on belly), and tonic-clonic seizure (wild jumping). While latency and frequency of facial and neck jerks reduce over the experiment, catalepsy parameters tend to increase. First clonic or tonic seizures appears in male and female animals after 2.2 ± 2.0 and 2.3 ± 0.21 PTZ injections, respectively, while tonic-clonic seizures (wild jumping) require 15.3±1.3 and 14.7±0.7 injections. Immunofluorescence exploration revealed a significant increase in GFAP (+) cells in the hippocampus of kindled rats compared to controls.