Cumulative concentration-response curves to isoproterenol were constructed in 74 preparations of human airways (group A) contracted with acetylcholine (80% of maximal contraction). In 52 bronchi (group A1), the maximal relaxation to isoproterenol represented at least 70% of the acetylcholine contraction (average 98% +/- 3) and the mean concentration (+/- SD) causing 50% of the relaxation (EC50) was 6.0 X 10(-8)M +/- 0.8. Resistance to isoproterenol (significant decrease of the maximal relaxation and right shift of the concentration-response curve) was provoked in 25 preparations by incubating them with isoproterenol (concentration 100 times higher than the individual EC50) for 30 min. The response to isoproterenol remained stable over the same time interval in eight control preparations. Incubation with isoproterenol did not modify the relaxing response to theophylline (n = 8). Indomethacin had no effect on the resistance provoked by isoproterenol incubation (n = 11). Incomplete relaxation to isoproterenol (maximal relaxation averaging 47% +/- 2 of the acetylcholine contraction) was observed in 22 preparations (group A2; mean EC50 = 1 X 10(-6)M +/- 0.2, significantly different [p less than 0.001] from group A1). Such preparations could be completely relaxed by theophylline (n = 7). For the whole group A, a significant negative correlation was found between isoproterenol EC50 and the magnitude of the maximal relaxation to isoproterenol (expressed as percent of acetylcholine contraction). There was no significant correlation between acetylcholine EC50 and isoproterenol maximum relaxation. Spontaneous resistance to isoproterenol was neither related to the technique of isoproterenol administration (cumulative versus noncumulative; n = 11) nor the magnitude of acetylcholine contraction (70% and 95% of maximal contraction; 14 bronchi, group B).
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0091-6749(84)90235-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Kinetics of recovery and normalization of running biomechanics following aerobic-based exercise-induced muscle damage in recreational male runners.
J Sci Med Sport
January 2025
Department of Health Promotion, School of Public Health, Faculty of Medical and Health Sciences, Sylvan Adams Sports Institute, Tel-Aviv University, Israel. Electronic address:
Objectives: The study aimed to examine the effects of exercise-induced muscle damage on running kinetics.
Design: Twenty-six adult recreational male runners performed 60 min of downhill running (-10 %) at 65 % of maximal heart rate. Running gait changes, systemic and localized muscle damage markers were assessed pre - and post-exercise induced muscle damage protocol.
Integrated Sensing and Communication Target Detection Framework and Waveform Design Method Based on Information Theory.
Sensors (Basel)
January 2025
School of Aeronautics and Astronautics, University of Electronic Science and Technology of China, Chengdu 611731, China.
Target detection is a core function of integrated sensing and communication (ISAC) systems. The traditional likelihood ratio test (LRT) target detection algorithm performs inadequately under low signal-to-noise ratio (SNR) conditions, and the performance of mainstream orthogonal frequency division multiplexing (OFDM) waveforms declines sharply in high-speed scenarios. To address these issues, an information-theory-based orthogonal time frequency space (OTFS)-ISAC target detection processing framework is proposed.
View Article and Find Full Text PDFSex differences in ventricular-vascular interactions associated with aerobic capacity.
Echo Res Pract
January 2025
School of Human Kinetics, Trinity Western University, CANIL Building, Rm. 115 22500 University Drive, Langley, BC, V2Y 1Y1, Canada.
Background: Aerobic capacity measured by maximal oxygen uptake (VOmax) is related to functional capacity and is a strong independent predictor of all-cause and disease-specific mortality. Sex-specific cardiac and vascular responses to endurance training have been observed, however, their relative contributions to VOmax are less understood. The purpose of this study was to evaluate sex-specific ventricular-vascular interactions associated with VOmax in healthy males and females.
View Article and Find Full Text PDFThe N-Terminal Mutations of cMyBP-C Affect Calcium Regulation, Kinetics, and Force of Muscle Contraction.
Int J Mol Sci
December 2024
Institute of Immunology and Physiology, Russian Academy of Sciences, 620049 Yekaterinburg, Russia.
The cardiac myosin binding protein-C (cMyBP-C) regulates cross-bridge formation and controls the duration of systole and diastole at the whole heart level. As known, mutations in cMyBP-C increase the cross-bridge number and rate of their cycling, hypercontractility, and myocardial hypertrophy. We investigated the effects of the mutations D75N and P161S of cMyBP-C related to hypertrophic cardiomyopathy on the mechanism of force generation in isolated slow skeletal muscle fibers.
View Article and Find Full Text PDFThe Effect of Training Experience on Cardiac Morphology in Resistance Exercise Practitioners: A Study on Left Ventricular Systolic and Diastolic Parameters and Left Atrium Mechanical Functions.
Medicina (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.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!