title: Eugenol dilates rat cerebral arteries by inhibiting smooth muscle cell voltage-dependent calcium channels.
abstract: Plants high in eugenol, a phenylpropanoid compound, are used as folk medicines to alleviate diseases including hypertension. Eugenol has been demonstrated to relax conduit and ear arteries and reduce systemic blood pressure, but mechanisms involved are unclear. Here, we studied eugenol regulation of resistance-size cerebral arteries that control regional brain blood pressure and flow and investigated mechanisms involved. We demonstrate that eugenol dilates arteries constricted by either pressure or membrane depolarization (60 mM K) in a concentration-dependent manner. Experiments performed using patch-clamp electrophysiology demonstrated that eugenol inhibited voltage-dependent calcium (Ca) currents, when using Ba as a charge carrier, in isolated cerebral artery smooth muscle cells. Eugenol inhibition of voltage-dependent Ca currents involved pore block, a hyperpolarizing shift (∼-10 mV) in voltage-dependent inactivation, an increase in the proportion of steady-state inactivating current, and acceleration of inactivation rate. In summary, our data indicate that eugenol dilates cerebral arteries by means of multimodal inhibition of voltage-dependent Ca channels.
authors.affiliation: *Department of Physiology, University of Tennessee Health Science Center, Memphis, TN; and †Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Dieniffer
authors.initials: D
authors.lastname: Peixoto-Neves
authors.forename: Jose Henrique
authors.initials: JH
authors.lastname: Leal-Cardoso
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Jaggar
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D002536:Cerebral Arteries / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005054:Eugenol / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D014665:Vasodilator Agents; D005054:Eugenol