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PMID: 7230019 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Voltage-clamp investigations of membrane currents underlying pace-maker activity in rabbit sino-atrial node.

The Journal of physiology ·Vol. 308 ·1980-11-00 ·Pages 331-51

Brown H, Difrancesco D

Abstract

1. Small preparations of spontaneously beating rabbit sino-atrial node have been investigated using the two micro-electrode voltage-clamp technique. 2. Hyperpolarizing clamp pulses given from holding potentials of about -45 mV reveal a time-dependent change of a membrane current, if, which is shown to overlap the pace-maker range (-65 mV to -45 mV) for these preparations. 3. The changes in if are shown to be quite distinct from the de-activation of the time-dependent outward current, iK. 4. The time-dependent changes of the if system increase during adrenaline application and therefore contribute to the chronotropic action of adrenaline on the heart. 5. Evidence for a link between slow inward current (iSi) and time-dependent outward current (iK) in rabbit sino-atrial node is presented and assessed.

MeSH Terms
Animals Epinephrine/pharmacology Gallopamil/pharmacology In Vitro Techniques Membrane Potentials/drug effects Potassium/physiology Rabbits Sinoatrial Node/drug effects,physiology Stimulation, Chemical Temperature Tetrodotoxin/pharmacology
Chemicals
Gallopamil Tetrodotoxin Potassium Epinephrine
Authors & Affiliations
2 authors, click to expand affiliations / ORCID
Brown H
Difrancesco D
References (28)
28 references, click to expand
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Article Info
Journal
The Journal of physiology
Abbr.
J Physiol
ISSN
0022-3751
DOI
10.1113/jphysiol.1980.sp013474
Published
1980-11-00
Pages
331-51
Language
English
Region
England
NLM ID
0266262
PMCID
PMC1274551
Subset
IM
External Links
PubMed source DOI: 10.1113/jphysiol.1980.sp013474 PMC Full Text View journal details
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