High Frequency Deep Brain Stimulation and the Urine Storage Function in Awake Pigs

Methods In 6 female Goettingen minipigs (weight 22–47 kg), 5 of which had been intoxicated with 1-methyl-4-phenyl1,2,3,6-tetrahydropyridine (MPTP), a unilateral electrode for chronic stimulation was placed in the subthalamic area. Correct localization of the electrode was verified by peroperative MRI-scan and examined by autopsy at study-termination after 12-14 months of stimulation-treatment. The electrode was connected to a subcutaneous battery unit (Itrel® II quadripolar implantable pulse generator, Medtronic®, Minneapolis, Minnesota, USA). Stimulation mode and -parameters were controlled telemetrically and set to unipolar pulses, 160 pulses/s, 3 V, pulsewidth 60 s, continuous stimulation, thus corresponding to the settings used in humans treated for Parkinsonism. In the awake pig a transurethral catheter was placed and cystometries were performed as a continuous infusion of room temperature saline with a rate of 60 ml/minute. Four cystometries were compared: Cystometry 1, stimulation on for six months; Cystometry 2, stimulation off for less than 45 minutes; Cystometry 3, stimulation off for two days; Cystometry 4, stimulation on for less than 25 minutes. Data on cystometric capacity and on intravesical pressure rise on filling were evaluated.