Geraniol Blocks Calcium and Potassium Channels in the Mammalian Myocardium: Useful Effects to Treat Arrhythmias

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 AE 160 lM) and diminished the positive inotropism of CaCl 2 and BAY K8644. In cardiomyocytes, the I Ca,L was reduced by 50.7% (n = 5) after perfusion with 300 lM 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 K1 ) (33.7%, n = 4). In isolated hearts, geraniol increased PRi and QTi 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.

The Differential Effects of a Selective Kappa-Opioid Receptor Agonist, U50488, in Guinea Pig Heart Tissues

“…In general, agents and interventions that increase K + conductance (G k ) shorten action potential duration (APD) and tend to have negative inotropic effects, whereas agents that decrease K + current lengthen APD and may have positive inotropic effects [ 27 ]. Therefore, the shortening of the action potential duration is a possible mechanism responsible for the negative inotropic effect of U50488.…”

Structured plant metabolomics for the simultaneous exploration of multiple factors

“…Higher concentrations of useable nitrogen also enhanced the accumulation of linalool and citronellol by Saccharomyces cerevisiae 33. Geraniol blocks calcium and potassium channels in mammalian cells34 and similar cyclic nucleotide-gated ion channels are found in plants35.…”

Pharmacological Properties of Geraniol – A Review

“…GE also decreased left ventricular pressure (83 %) and the heart rate (16.5 %). GE also prolonged the onset of ouabain-induced arrhythmias by 128 % and decreased the resting tension by 30 % [64].…”