Abstracts

RATIONALE: To investigate the alleged suppressive effect of one hertz electrical stimulation on fully kindled seizures in rats. METHODS: Male Sprague-Dawley rats, implanted bilaterally with bipolar electrodes in the basolateral amygdala, were stimulated once daily with 60 hertz current for 2 seconds (biphasic sine wave, 16.7 milliseconds pulse width) until eight class 5 seizures, graded according to Racine's scale, were elicited in ten consecutive trials. After this criterion was met, half of the rats were stimulated with one hertz current (biphasic sine wave, 16.7 milliseconds pulse width) for 300 seconds at half the intensity used for kindling for 5 days, as the first experiment. After the one hertz stimulation, all the rats were "re-kindled" (10 consecutive daily trials) with the same kindling parameters. All the rats were rested for 15 days and then "kindled" again using the same parameters and criteria as in the first experiment. After eight class 5 seizures had been elicited in ten consecutive trials, half the rats were stimulated with a one hertz current (biphasic sine wave, 16.7 milliseconds pulse width) for 600 seconds at double the intensity used for kindling for 5 days, as the second experiment. After the one hertz stimulation, all the rats were "re-kindled" (10 consecutive daily trials) once more. In both of the experiments, the rats used as control did not receive one hertz stimulation. RESULTS: In the first experiment, frequency of class 5 seizures was unaltered by one hertz stimulation. However longer and more intense one hertz stimulation decreased the number of class 5 seizures in 3 out of 8 rats in the second experiment. CONCLUSIONS: One hertz stimulation may have a parameter dependant suppressive effect on kindled seizures. These observations are currently being expanded to include more animals and parameters.