title: In-vitro characterization of the pharmacological effects induced by (-)-α-bisabolol in rat smooth muscle preparations.
abstract: The present study deals with the pharmacological effects of the sesquiterpene alcohol (-)-α-bisabolol on various smooth-muscle preparations from rats. Under resting tonus, (-)-α-bisabolol (30-300 µmol/L) relaxed duodenal strips, whereas it showed biphasic effects in other preparations, contracting endothelium-intact aortic rings and urinary bladder strips, and relaxing these tissues at higher concentrations (600-1000 µmol/L). In preparations precontracted either electromechanically (by 60 mmol/L K(+)) or pharmacomechanically (by phenylephrine or carbachol), (-)-α-bisabolol showed only relaxing properties. The pharmacological potency of (-)-α-bisabolol was variable, being higher in mesenteric vessels, whereas it exerted relaxing activity with a lesser potency on tracheal or colonic tissues. In tissues possessing spontaneous activity, (-)-α-bisabolol completely decreased spontaneous contractions in duodenum, whereas it increased their amplitude in urinary bladder tissue. Administered in vivo, (-)-α-bisabolol attenuated the increased responses of carbachol in tracheal rings of ovalbumin-sensitized rats challenged with ovalbumin, but was without effect in the decreased responsiveness of urinary bladder strips in mice treated with ifosfamide. In summary, (-)-α-bisabolol is biologically active in smooth muscle. In some tissues, (-)-α-bisabolol preferentially relaxed contractions induced electromechanically, especially in tracheal smooth muscle. The findings from tracheal rings reveal that (-)-α-bisabolol may be an inhibitor of voltage-dependent Ca(2+) channels.
authors.affiliation: Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: Rodrigo J B
authors.initials: RJ
authors.lastname: de Siqueira
authors.forename: Walter B S
authors.initials: WB
authors.lastname: Freire
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Vasconcelos-Silva
authors.forename: Patrícia A
authors.initials: PA
authors.lastname: Fonseca-Magalhães
authors.forename: Francisco J B
authors.initials: FJ
authors.lastname: Lima
authors.forename: Teresinha S
authors.initials: TS
authors.lastname: Brito
authors.forename: Lívia T C
authors.initials: LT
authors.lastname: Mourão
authors.forename: Ronaldo A
authors.initials: RA
authors.lastname: Ribeiro
authors.forename: Saad
authors.initials: S
authors.lastname: Lahlou
authors.forename: Pedro J C
authors.initials: PJ
authors.lastname: Magalhães
mesh_terms: D000818:Animals; D002217:Carbachol / Q000037:antagonists & inhibitors / Q000494:pharmacology; D003556:Cystitis / Q000139:chemically induced / Q000188:drug therapy; D004195:Disease Models, Animal; D004386:Duodenum / Q000187:drug effects / Q000502:physiology; D007069:Ifosfamide; D066298:In Vitro Techniques; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy; D008297:Male; D000081222:Monocyclic Sesquiterpenes; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D010047:Ovalbumin; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012717:Sesquiterpenes / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology
chemical_list: D000081222:Monocyclic Sesquiterpenes; D012717:Sesquiterpenes; D010656:Phenylephrine; C004497:bisabolol; D002217:Carbachol; D010047:Ovalbumin; D007069:Ifosfamide