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Associating high intensity and modulated frequency of TENS delays analgesic tolerance in rats
Author(s) -
Lima L.V.,
Cruz K.M.L.,
Abner T.S.S.,
Mota C.M.D.,
Agripino M.E.J.,
SantanaFilho V.J.,
DeSantana J.M.
Publication year - 2015
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.555
Subject(s) - analgesic , intensity (physics) , transcutaneous electrical nerve stimulation , stimulation , medicine , pain tolerance , anesthesia , threshold of pain , physics , alternative medicine , pathology , quantum mechanics
Background Transcutaneous electrical nerve stimulation ( TENS ) is a non‐invasive analgesic resource extensively used in painful conditions. However, preclinical studies suggest that the prolonged use of TENS results in the development of tolerance to its analgesic effect. The present study investigated the analgesic effect and development of tolerance to TENS with four different stimulation protocols. Methods Male W istar rats induced with joint inflammation were divided into four groups: sensory intensity, low motor intensity, high motor intensity and sham groups. TENS was applied daily for 20 min with alternating frequency between 4 and 100 Hz until tolerance development was evidenced. Mechanical hyperalgesia was measured before and after each TENS daily application. Results After TENS , tolerance was evidenced There was a significant reduction in the mechanical withdrawal threshold in all groups 24 h after induction of inflammation ( p < 0.01). We observed a loss of analgesic efficacy of TENS around the 12th, 19th and 19th days in the groups treated with sensory intensity, low motor intensity and high motor intensity, respectively ( p < 0.02) when analysed using paired measurements and compared with the control. Conclusions The association between frequency variation and intensity at motor level promotes a delay in the development of analgesic tolerance to TENS , optimizing and extending its therapeutic effectiveness.