Transcranial magnetic stimulation reduces nociceptive threshold in rats.
Transcranial magnetic stimulation (TMS) is a procedure that uses magnetic fields to stimulate or inhibit nerve cells in the brain noninvasively. TMS induces an electromagnetic current in the underlying cortical neurons. Varying frequencies and intensities of TMS increase or decrease excitability in the cortical area directly targeted. It has been suggested that TMS has potential in the treatment of some neurological disorders such as Parkinson's disease, stroke, and depression. Initial case reports and open label trials reported by several groups support the use of TMS in pain treatment. In the present study, we evaluated the effect of TMS on the nociceptive threshold in the rat. The parameters used were a frequency of 60 Hz and an intensity of 2 and 6 mT for 2 hr twice per day. After 5 days of TMS treatment, rats were evaluated for mechanical, chemical, and cold stimulation. We observed a significant reduction in the nociceptive threshold in TMS-treated rats but not in sham-treated rats in all behavioral tests evaluated. When TMS treatment was stopped, a slow recovery to normal mechanic threshold was observed. Interestingly, i.c.v. MK-801 or CNQX administration reverted the TMS-induced pronociception. The results suggest that high-frequency TMS can alter the nociceptive threshold and produce allodynia in the rats; results suggest the involvement of NMDA and AMPA/KA receptors on TMS-induced allodynia in the rat.
Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México.
Mónica
M
Ambriz-Tututi
Violeta
V
Sánchez-González
René
R
Drucker-Colín
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology / Q000627:therapeutic use; D000704:Analysis of Variance; D000818:Animals; D019540:Area Under Curve; D016291:Dizocilpine Maleate / Q000494:pharmacology / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D006930:Hyperalgesia / Q000503:physiopathology* / Q000628:therapy; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D010812:Physical Stimulation / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation
D018691:Excitatory Amino Acid Antagonists; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione