title: Investigation of terpinen-4-ol effects on vascular smooth muscle relaxation.
abstract: OBJECTIVE
  This study investigated the mechanisms underlying the vascular effects of terpinen-4-ol in isolated rat aortic ring preparations.
  
  
  METHODS
  The thoracic aortae of healthy rats were submitted to isometric tension recording. Membrane resting potential and input membrane resistance were measured by conventional microelectrode technique.
  
  
  RESULTS
  Terpinen-4-ol reversibly relaxed endothelium-containing preparations pre-contracted with high K(+) and phenylephrine with IC50 values of 421.43 μM and 802.50 μM, respectively. These effects were significantly reduced by vascular endothelium removal. In Ca(2+)-free and high K(+) (80 mM) medium, the contractions produced by Ba(2+) were reduced by terpinen-4-ol (100-1000 μM) in a concentration-dependent manner. In aortic rings maintained under Ca(2+)-free conditions, terpinen-4-ol significantly reduced the contractions induced by either phenylephrine (1 μM) or phorbol 12,13-dibutyrate (1 μM). Terpinen-4-ol (10-1000 μM) also relaxed the contractions evoked by BAYK-8644 (3 μM) with an IC50 of 454.23 μM. Neither membrane resting potential nor input resistance of smooth muscle cells was altered by terpinen-4-ol exposure.
  
  
  CONCLUSIONS
  The present results suggest that terpinen-4-ol induced vascular smooth muscle relaxation that was preferentially due to the inhibition of electromechanical pathways related to calcium influx through voltage-operated calcium channels.
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Rebeca Peres Moreno
authors.initials: RP
authors.lastname: Maia-Joca
authors.affiliation: Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Humberto Cavalcante
authors.initials: HC
authors.lastname: Joca
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Francisca Jéssica Penha
authors.initials: FJ
authors.lastname: Ribeiro
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Renata Vieira
authors.initials: RV
authors.lastname: do Nascimento
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Kerly Shamyra
authors.initials: KS
authors.lastname: Silva-Alves
authors.affiliation: Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. Electronic address: jcruz@icb.ufmg.br.
authors.forename: Jader S
authors.initials: JS
authors.lastname: Cruz
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Andrelina Noronha
authors.initials: AN
authors.lastname: Coelho-de-Souza
authors.affiliation: Superior Institute of Biomedical Sciences, Universidade Estadual do Ceará, Fortaleza, CE, Brazil. Electronic address: lealcard@gmail.com.
authors.forename: José Henrique
authors.initials: JH
authors.lastname: Leal-Cardoso
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects; D005260:Female; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013729:Terpenes / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D015220:Calcium Channels; D013729:Terpenes; D014665:Vasodilator Agents; C034019:terpinenol-4; D002118:Calcium
keywords: Excitation–contraction coupling; Monoterpenoids; Terpinen-4-ol; Vascular smooth muscle; Vasorelaxant