Quantification of the rat left ventricle force and Ca2+-frequency relationships: similarities to dog and human
Abstract
OBJECTIVE: To measure and quantify the force-frequency (FFR) and Ca(2+)-frequency (CaFR) relationships in isolated rat left ventricular (LV) muscle at physiological heart rates and compare the obtained FFR to that measured in larger mammalian muscle from dog and human using the same experimental protocol. METHODS: Rat papillary muscle was isolated from the LV of adult male Sprague-Dawley rats, and dog and human muscles were from free-wall LV biopsies, loaded with the Ca(2+) indicator Fura-2, allowed to recover from isolation trauma and then subjected to direct electrical stimulation while measuring force production and intracellular Ca(2+) transients. RESULTS: We obtained a positive FFR between 1 and 4 Hz that is qualitatively similar to that found in isolated LV epicardial muscle strips from dogs and humans with normal LV function. The FFR reflects the cytosolic Ca(2+) transients in amplitude. Isoproterenol yielded an enhancement in force, but flattening of the FFR, whereas cyclopiazonic acid caused depression of FFR amplitude without changing frequency-dependent shape. CONCLUSION: We describe an experimental protocol that consistently yields positive FFRs in rat, dog and human LV muscle at stimulation rates between 1 and 4 Hz, without significant qualitative differences. We attribute previously observed negative FFR in rat muscle to an increase in SERCA activity early after excision and preparation of the muscle strips.
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Canine myocardium, similar to healthy human myocardium, exhibits a positive force-frequency relationship as determined by isometrically contracting muscles ex vivo where tension increases 185% from 1 Hz to 3.4 Hz.
“canine myocardium, similar to healthy human myocardium, exhibit a positive force-frequency relationship as determined by isometrically contracting muscles ex vivo where tension increases 185% from 1 Hz to 3.4 Hz (Taylor, Parilak, LeWinter, & Knot, 2004).”
From Small and large animal models in cardiac contraction research: advantages and disadvantages (2014) · cites this paper as Taylor, et al., 2004
The study of canine force-frequency relationship by Taylor et al. was performed at a sub-physiological temperature of 30 degrees C.
“We must point out that this particular study was performed at sub-physiological temperature of 30 °C.”
From Small and large animal models in cardiac contraction research: advantages and disadvantages (2014) · cites this paper as Taylor, et al., 2004
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References 37 · Cited by 29
Research works printed but not linked: 3
- Bowditch HP. Ueber die Eigenthuemlichkeit der Raizbarkeit, welche die Muskelfasern des Herzens zeigen. Ber Sachs Ges (Akad) Wiss 1871;23:652 -89.
- Pieske B, Maier LS, Bers DM, Hasenfuss G. Ca2+ handling and sarcoplasmic reticulum Ca2+ content in isolated failing and nonfail- ing human myocardium. Circ Res 1999;85:38 -46.
- Opie L. The heart: physiology, from cell to circulation. 34. Phiadel- phia (PA): Lippincott-Raven Publishers, 1998.
- Authors
- Taylor, D.
- Affiliations
- University of Florida (US)
- Corresponding author
- Taylor, D
- Venue
- Cardiovascular Research
- Publisher
- Oxford University Press (OUP)
- Published
- 2004-01-01
- Volume
- 61
- Issue
- 1
- Pages
- 77-86
- ISSN
- 0008-6363 (ISSN-L)
- OpenAlex
- W2022204383
- Cited by
- 29
- References
- 37
- Citations by year
- 2025: 1 · 2024: 1 · 2023: 1 · 2022: 2 · 2021: 1 · 2020: 1 · 2019: 1 · 2018: 1 · 2016: 2 · 2015: 3 · 2014: 1 · 2013: 2 · 2012: 2
- FWCI
- 0.66
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Cardiovascular Research (publishedVersion)
- PubMed (publishedVersion)
- Funders
- American Heart Association
- National Institutes of Health (5r01hl061556-05)
- National Heart, Lung, and Blood Institute (HL61556, HL50287, R01HL050287)
- Topics
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiac electrophysiology and arrhythmias
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiovascular Function and Risk Factors
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiac pacing and defibrillation studies
- Keywords
- force-frequency relationship, left ventricular muscle, calcium transients, papillary muscle, isoproterenol, cyclopiazonic acid, SERCA, cross-species comparison, rats, dogs, human, fura-2
- MeSH terms
- Aged, Animals, Biomechanical Phenomena, Calcium, Calcium Channel Blockers, Cardiotonic Agents, Coronary Disease, Dogs, Electric Stimulation, Female, Heart Rate, Humans, Indoles, Isoproterenol, Male, Myocardial Contraction, Myocardium, Rats, Sprague-Dawley, Rats, In Vitro Techniques
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