Author(s)

Sergio A. Sacchettoni^1,2, Juan P. Abud¹, Napoleon Torres³, Yngo García^1,4, Daniel A. Onay¹, Juan Luis Rodulfo¹, Juan Félix Del Corral², Pedro Rada⁴, Rafael Galera^1,2, Luis Hernández⁴

¹Service of Neurosurgery, Hospital and School of Medicine JJ Vargas, Universidad Central de Venezuela, Caracas, Venezuela.
²Unit of Surgical Research, Hospital and School of Medicine JJ Vargas, Universidad Central de Venezuela, Caracas, Venezuela.
³Univ. Grenoble Alpes, CEA, LETI, Clinatec, France.
⁴Laboratory of Behavioral Physiology, Faculty of Medicine, Universidad de Los Andes, Mérida, Venezuela.

In Parkinson’s disease (PD), dopaminergic neurons reduce the regulation of glutamatergic (glutamate-Glu) input from the cortex to neostriatum (caudate and putamen nuclei) consequently leading to a hyperactivity of globus pallidus internae (GPi) neurons that release gamma-amino-butyric acid (GABA) into the thalamic ventrolateral (VL) nucleus. The objective of the present experiment was to measure changes in GABA and Glu in the caudate and the thalamus of 2 patients during the application of electrical stimuli following either a pallidotomy or a thalamotomy. Proper insertion of the electrode was tested by applying high frequency electrical pulses (HFEP). During these procedures, we obtained neurochemical information placing cerebral (CMD) microdialysis probes in caudate nucleus and VL nucleus of ipsi- and contra-lateral thalamus. In VL thalamus, extracellular GABA decreased during HFEP, tending to reach previous levels once HFEP was finalized. Following the pallido- or thalamotomy GABA decreased again. Similarly, in the contralateral VL thalamus, extracellular GABA levels showed a similar but less pronounced profile but did not show any decrement after the lesion. Caudate Glu decreases when HFEP is applied to the GPi and recovers to previous levels after HFEP, but did not decrease again after lesion (GPi-tomy), instead it continued to rise. These results suggest that HFEP exerts a similar but reversible biochemical effect as thermopallido- or thermothalamotomy on GABA extracellular concentration in the ipsilateral VL thalamus. We also observe a distant effect of HFEP, but not of thermolesion, on contralateral thalamic GABA and ipsilateral caudate Glu.

Cerebral Microdialysis, Parkinson’s Disease, Pallidotomy, Thalamotomy, Basal Ganglia Circuit, Cerebral Electromodulation, DBS

Sacchettoni, S. , Abud, J. , Torres, N. , García, Y. , Onay, D. , Rodulfo, J. , Corral, J. , Rada, P. , Galera, R. and Hernández, L. (2020) Dynamic Cerebral Microdialysis during Pallidotomy and Thalamotomy in Parkinson’s Disease: A Preliminary Neurochemical Study. Open Journal of Modern Neurosurgery, 10, 284-296. doi: 10.4236/ojmn.2020.102031.