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http://purl.uniprot.org/citations/15803439http://www.w3.org/2000/01/rdf-schema#comment"

Introduction

The effect of angiotensin (1-7) (Ang 1-7) on membrane potential and excitability of rat heart muscle under ischaemia/reperfusion was investigated.

Materials and methods

The hearts of adult rats were removed under deep anaesthesia and perfused using the Langendorff method. After 40 minutes of global no-flow ischaemia, the heart was reperfused for five minutes and the right ventricle was dissected out and transferred to a transparent chamber, through which normal oxygenated Krebs solution flowed continuously (37 degrees C). Measurements of membrane potential were performed using an intracellular microelectrode connected to a high impedance preamplifier. The muscle was stimulated with rectangular current pulses (3 ms duration; 0.6 Hz) generated by an electronic stimulator and isolation unit. To study the influence of Ang (1-7) on sodium pump current, isolated myocytes were voltage-clamped at -40 mV and the current generated by the pump was recorded before and after the administration of Ang (1-7) (10-8 M) to the bath.

Results

Ang (1-7) (10-8 M) hyperpolarised the ischaemic heart fibre and re-established impulse propagation. The increment of resting potential was related to the activation of the sodium pump. Indeed, Ang (1-7) (10-8 M) enhanced the transient outward current generated by an electrogenic sodium pump. Both effects of Ang (1-7) on membrane potential and pump current were abolished by ouabain (10-7 M). The cardiac refractoriness was also increased by Ang (1-7) (10-8 M).

Conclusions

Ang (1-7) activates the sodium pump, hyperpolarises the heart cell and re-establishes the impulse conduction during ischaemia/reperfusion. These effects of Ang (1-7), and the increment of cardiac refractoriness, provide an explanation for the reduced incidence of arrhythmias during ischaemia/reperfusion in the presence of Ang (1-7)."xsd:string
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/volume"5"xsd:string
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/date"2004"xsd:gYear
http://purl.uniprot.org/citations/15803439http://www.w3.org/2004/02/skos/core#exactMatchhttp://purl.uniprot.org/pubmed/15803439
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/name"J Renin Angiotensin Aldosterone Syst"xsd:string
http://purl.uniprot.org/citations/15803439http://purl.org/dc/terms/identifier"doi:10.3317/jraas.2004.041"xsd:string
http://purl.uniprot.org/citations/15803439http://xmlns.com/foaf/0.1/primaryTopicOfhttps://pubmed.ncbi.nlm.nih.gov/15803439
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/title"Angiotensin (1-7) re-establishes impulse conduction in cardiac muscle during ischaemia-reperfusion. The role of the sodium pump."xsd:string
http://purl.uniprot.org/citations/15803439http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/author"De Mello W.C."xsd:string
http://purl.uniprot.org/citations/15803439http://purl.uniprot.org/core/pages"203-208"xsd:string