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Geraniol Blocks Calcium and Potassium Channels in the Mammalian Myocardium: Useful Effects to Treat Arrhythmias
Author(s) -
MenezesFilho José Evaldo Rodrigues,
Gondim Antônio Nei Santana,
Cruz Jader Santos,
Souza Américo Azevedo,
Santos José Nilson Andrade dos,
CondeGarcia Eduardo Antônio,
Sousa Damião Pergentino,
Santos Michel Santana,
Oliveira Evaleide Diniz,
Vasconcelos Carla Maria Lins
Publication year - 2014
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/bcpt.12274
Subject(s) - geraniol , repolarization , chemistry , medicine , chronotropic , ouabain , cardiology , pharmacology , sodium , electrophysiology , heart rate , blood pressure , essential oil , chromatography , organic chemistry
Abstract Geraniol is a monoterpene present in several essential oils, and it is known to have a plethora of pharmacological activities. In this study, we explored the contractile and electrophysiological properties of geraniol and its antiarrhythmic effects in the heart. The geraniol effects on atrial contractility, L‐type Ca 2+ current, K + currents, action potential ( AP ) parameters, ECG profile and on the arrhythmia induced by ouabain were evaluated. In the atrium, geraniol reduced the contractile force (~98%, EC = 1,510 ± 160 μM) and diminished the positive inotropism of CaCl 2 and BAY K8644. In cardiomyocytes, the I C a,L was reduced by 50.7% (n = 5) after perfusion with 300 μM geraniol. Moreover, geraniol prolonged the AP duration ( APD ) measured at 50% (n = 5) after repolarization, without changing the resting potential. The increased APD could be attributed to the blockade of the transient outward K + current (I to ) (59.7%, n = 4), the non‐inactivation K + current (I ss ) (39.2%, n = 4) and the inward rectifier K + current ( I K 1 ) (33.7%, n = 4). In isolated hearts, geraniol increased PR i and QT i without affecting the QRS complex (n = 6), and it reduced both the left ventricular pressure (83%) and heart rate (16.5%). Geraniol delayed the time to onset of ouabain‐induced arrhythmias by 128%, preventing 30% of the increase in resting tension (n = 6). Geraniol exerts its negative inotropic and chronotropic responses in the heart by decreasing both L‐type Ca 2+ and voltage‐gated K + currents, ultimately acting against ouabain‐induced arrhythmias.