title: Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity.
abstract: Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: O S
authors.initials: OS
authors.lastname: Franco
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: F S
authors.initials: FS
authors.lastname: Paulitsch
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: A P C
authors.initials: AP
authors.lastname: Pereira
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: A O
authors.initials: AO
authors.lastname: Teixeira
authors.affiliation: Programa de Pós-Graduação em Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: C N
authors.initials: CN
authors.lastname: Martins
authors.affiliation: Departamento de Fisioterapia e Reabilitação, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil.
authors.forename: A M V
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Programa de Pós-Graduação em Ciências da Reabilitação, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brasil.
authors.forename: R D M
authors.initials: RD
authors.lastname: Plentz
authors.affiliation: Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: M C
authors.initials: MC
authors.lastname: Irigoyen
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Faculdade de Medicina, Universidade Federal do Rio Grande, Rio Grande, RS, Brasil.
authors.forename: L U
authors.initials: LU
authors.lastname: Signori
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose; D002317:Cardiovascular Agents / Q000494:pharmacology*; D002784:Cholesterol / Q000097:blood; D004906:Erythrocyte Count; D006225:Hand / Q000098:blood supply*; D006801:Humans; D007958:Leukocyte Count; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D014280:Triglycerides / Q000097:blood; D014508:Urea / Q000097:blood; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D014680:Veins / Q000187:drug effects
chemical_list: D001786:Blood Glucose; D002317:Cardiovascular Agents; D008075:Lipoproteins, HDL; D014280:Triglycerides; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D014508:Urea; D002784:Cholesterol; D000109:Acetylcholine