Propofol is a widely used intravenous general anesthetic. The negative inotropic effect of propofol has been best explained by inhibition of the L-type Ca(2+) current (I(Ca)). Using guinea-pig cardiac preparations, however, we found that the propofol concentration producing a 50% decrease in force of contraction was more than 10 times higher than that producing a 50% inhibition of I(Ca), implying that a compensatory mechanism may be present to counteract the negative inotropic effect associated with the I(Ca) inhibition. Consistent with I(Ca) inhibition, propofol produced a shortening of action potential duration (APD) in single cardiomyocytes. Yet, the concentrations necessary to shorten APD were greater than that for 50% inhibition of I(Ca). This was associated with the potent and effective inhibition of the slowly activating component of the delayed rectifier K(+) current (I(Ks)). Thus, the I(Ks) blockade with propofol may counterbalance the APD shortening evoked by its I(Ca) inhibition. Taken together, the negative inotropic effect of propofol is detectable only at supratherapeutic concentrations. At clinically relevant concentrations, the action potential prolongation mechanism due to I(Ks) inhibition appears to alleviate the reduction in transsarcolemmal Ca(2+) influx through L-type Ca(2+) channels, which may help to counteract the net negative inotropism of propofol.
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Life (Basel)
January 2025
Physiotherapy and Health Research Group (FYSA), Department of Physiotherapy, Faculty of Health Sciences-HM Hospitals, University Camilo José Cela, Villanueva de la Cañada, 28692 Madrid, Spain.
Background/objectives: Implementing and optimizing pelvic floor muscle (PFM) training programs is crucial for reducing the risk of dysfunctions, improving athletic performance, and enhancing quality of life for athletes. The aim of this study was to assess PFM activation in female athletes during postural challenges.
Methods: An observational and descriptive study was conducted with twenty-five female rugby players.
Cardiovasc Diabetol
January 2025
Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China.
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View Article and Find Full Text PDFFASEB J
January 2025
Shirley Ryan AbilityLab, Chicago, Illinois, USA.
Following injury, skeletal muscle undergoes repair via satellite cell (SC)-mediated myogenic progression. In SCs, the circadian molecular clock gene, Bmal1, is necessary for appropriate myogenic progression and repair with evidence that muscle molecular clocks can also affect force production. Utilizing a mouse model allowing for inducible depletion of Bmal1 within SCs, we determined contractile function, SC myogenic progression and muscle damage and repair following eccentric contractile-induced injury.
View Article and Find Full Text PDFPost-operative new-onset atrial fibrillation (POAF) is a possible complication following cardiac surgery. Digoxin is a drug with positive inotropic and negative chronotropic effects and is listed among antiarrhythmic drugs that can be prescribed in dogs with atrial fibrillation. This report aims at describing the use of digoxin in two dogs with persistent POAF after mitral valve repair.
View Article and Find Full Text PDFMedicina (Kaunas)
December 2024
Department of Rehabilitation Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
: Resistance exercises (REs) are a type of physical activity that individuals from many age groups have been doing recreationally, both as amateurs and professionally, in their daily lives in recent years. It is crucial to understand the effects of such sports on cardiac morphology in order to maximize the benefit of training and to tailor the training content accordingly. The aim of this study was to investigate the relationship between training experience (TE) and left ventricular (LV) systolic and diastolic parameters and left atrial (LA) mechanical function in healthy subjects who regularly performed RE for different durations.
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