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.

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Quercetin is a plant flavonoid with several biological activities. This study aimed to describe quercetin effects on contractile and electrophysiological properties of the cardiac muscle as well as on calcium handling. Quercetin elicited positive inotropism that was significantly reduced by propranolol indicating an involvement of the sympathetic nervous system. In cardiomyocytes, 30 μM quercetin increased I at 0 mV from -0.95 ± 0.01 A/F to -1.21 ± 0.08 A/F. The membrane potential at which 50% of the channels are activated (V ) shifted towards more negative potentials from -13.06 ± 1.52 mV to -19.26 ± 1.72 mV and did not alter the slope factor. Furthermore, quercetin increased [Ca ] transient by 28% when compared to control. Quercetin accelerated [Ca ] transient decay time, which could be attributed to SERCA activation. In resting cardiomyocytes, quercetin did not change amplitude or frequency of Ca sparks. In isolated heart, quercetin increased heart rate and decreased PRi, QTc and duration of the QRS complex. Thus, we showed that quercetin activates β-adrenoceptors, leading to increased L-type Ca current and cell-wide intracellular Ca transient without visible changes in Ca sparks.

Introduction: Several strength training protocols have been tested in the search for systemic adaptations to improve functionality in the elderly. For this purpose, integrated exercises aimed at improving essential movements can be an interesting strategy to improve the performance of activities of the daily living. Objective: To compare the effects of eight weeks of functional training with traditional strength training on the physical fitness of sedentary elderly women. Methods: Thirty-two elderly women were divided into functional training group (FT, n=16) and traditional training group (TT, n=16). For the verification of functional responses, the Senior Fitness Test battery was used, as well as complementary tests of strength and muscular power. The data were analyzed using a 2x2 ANOVA with post hoc Sidak test to verify the differences between the groups. Results: At the end of eight weeks, when compared to TT group, the FT group showed significant increases in balance/ agility variables (p=0.01; +7.6%), lower limbs strength (p=0.04; +15.3%), upper limbs strength (p=0.05; +11.7%), and cardiorespiratory power (p=0.05; +10.7%). However, in relation to flexibility tests and conventional tests of maximum dynamic force and muscular strength, there were no statistically significant differences between the groups. Conclusions: Both interventions are efficient to improve physical fitness of sedentary elderly women; however, functional training induces better adaptive responses to functionality when compared with traditional training. Level of Evidence I; Randomized clinical trial.