Levodopa enhances immobility induced by spinal cord electromagnetic stimulation in rats.
The repetitive ElectroMagnetic Stimulation (rEMS) is an innocuous method applied to modulate neurocircuits in real-time to study the physiology of the central nervous system and treat neuropsychiatric conditions. Preliminary data suggest that spinal rEMS induces behavioral changes in awake rats. However, the mechanisms behind this phenomenon remain largely unknown.



Twenty-five male Wistar rats were divided into five subgroups of five animals each: one subgroup was drug-free, two subgroups received Levodopa+Benserazide 250+25mg/kg for two or seven days, and the remaining two subgroups received Haloperidol 0.1 or 0.3mg/kg for two days. The animals were restrained during sham rEMS (day 1) followed by real rEMS of the cervicothoracic region at a different day (day 2 or 7, depending on subgroup). Four behavioral parameters were quantified: Walking, Climbing, Grooming, and Cornering.



rEMS reduced Walking and increased Cornering duration when applied over the cervicothoracic region of drug-free animals. A pretreatment with Levodopa+Benserazide for two or seven days induced an additional decrease in Walking after rEMS. This reduction was maximum after the treatment for seven days and associated with extinction of Climbing and increase in Cornering. A pretreatment with Haloperidol 0.1mg/kg reduced Grooming after rEMS, but did not prevent the reduction in Walking.



Cervicothoracic rEMS induced complex immobility responses that are in part modulated by dopaminergic pathways in rats. Further studies are necessary to determine the specific mechanisms involved.
Department of Anatomy and Morphofunctional Sciences, MSc Program, Universidade Federal do Ceará, Fortaleza, Brazil; Universidade Federal do Ceará, Fortaleza, Brazil; Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA.
Paulo M G
PM
Sales
Universidade Federal do Ceará, Fortaleza, Brazil.
Loraine M S
LM
de Andrade
Center for Clinical and Translational Sciences, The University of Texas Health Science Center at Houston, USA.
Meagan R
MR
Pitcher
Universidade Federal do Ceará, Fortaleza, Brazil; Department of Physiology and Pharmacology, Universidade Federal do Ceará, Fortaleza, Brazil.
Francisco H
FH
Rola
Department of Anatomy and Morphofunctional Sciences, MSc Program, Universidade Federal do Ceará, Fortaleza, Brazil; Universidade Federal do Ceará, Fortaleza, Brazil; Neurology Division, Department of Internal Medicine, Universidade Federal do Ceará, Fortaleza, Brazil. Electronic address: gondimfranc@gmail.com.
Francisco de A A
FA
Gondim
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001581:Benzothiadiazines / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D004347:Drug Interactions; D004574:Electromagnetic Fields; D006120:Grooming / Q000187:drug effects; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D017208:Rats, Wistar; D013116:Spinal Cord / Q000502:physiology*; D013239:Stereotyped Behavior / Q000187:drug effects
D001581:Benzothiadiazines; D015259:Dopamine Agents; C004463:benzothiazide; D007980:Levodopa
Behavioral changes; Catatonia; Rats; Repetitive electromagnetic stimulation; Spinal cord