Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/67245
Author(s): Correia-Pinto, J
Henriques-Coelho, T
Oliveira, SM
Leite-Moreira, AF
Title: Distinct load dependence of relaxation rate and diastolic function in Oryctolagus cuniculus and Ratus norvegicus
Issue Date: 2003
Abstract: This study investigated potential differences on load dependence of relaxation rate and diastolic function between Oryctolagus cuniculus and Ratus norvegicus, which have constitutive differences in the mechanisms involved in myocardial inactivation. Load dependence of relaxation rate and diastolic function were evaluated with the response of left ventricular time constant tau and diastolic pressure-dimension relation to beat-to-beat aortic constrictions in open-chest rabbits and rats. Afterload levels were normalized, being expressed as a percentage of peak isovolumetric pressure (relative load). In control heartbeats, relaxation rate and diastolic function were similar in the two animal species. They presented, however, distinct responses to afterload elevations. In rabbits, time constant decreased approximately 7% and diastolic pressure-dimension relation remained unchanged when afterload was elevated to a relative load of 73-76%. Above this afterload level, a significant deceleration of relaxation rate (increase of time constant) and an upward shift of diastolic pressure-dimension relation were observed. In rats, afterload elevations accelerated pressure fall up to a relative load of 97-100% and no afterload-induced shift of the diastolic pressure-dimension relation was observed. This study provides, therefore, evidence that Oryctolagus cuniculus has lower afterload reserve of myocardial relaxation and diastolic function than Ratus norvegicus.
Subject: Ciências médicas e da saúde
Medical and Health sciences
Scientific areas: Ciências médicas e da saúde
Medical and Health sciences
URI: https://repositorio-aberto.up.pt/handle/10216/67245
Document Type: Artigo em Revista Científica Internacional
Rights: openAccess
License: https://creativecommons.org/licenses/by-nc/4.0/
Appears in Collections:FMUP - Artigo em Revista Científica Internacional

Files in This Item:
File Description SizeFormat 
81590.pdf290.67 kBAdobe PDFThumbnail
View/Open


This item is licensed under a Creative Commons License Creative Commons