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Electrophysiological effects of adenosine and adenosine triphosphate on sheep Purkinje fibres under normal and simulated ischaemic conditions
Author(s) -
BoachieAnsah G.,
Kane K.A.,
Parratt J.R.
Publication year - 1989
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1989.tb11947.x
Subject(s) - adenosine , electrophysiology , depolarization , purkinje fibers , adenosine triphosphate , membrane potential , medicine , chemistry , endocrinology , resting potential , biophysics , biology
1 The electrophysiological effects of adenosine and adenosine triphosphate (ATP) were examined in sheep Purkinje fibres, superfused in vitro with either a normal or a hypoxic, hyperkalaemic and acidotic physiological salt solution (PSS). The ability of adenosine to modify the effects of noradrenaline on action potential characteristics was also investigated. 2 The only statistically significant effects of adenosine (10 −6 ‐10 −4 m ) and of ATP (10 −6 ‐10 −4 m ) on normal action potential characteristics were a slight dose‐dependent shortening of the action potential by adenosine and a depolarization by ATP, 10 −4 m . 3 Superfusion with a hypoxic, hyperkalaemic and acidotic PSS caused marked reductions in resting membrane potential, upstroke and duration of the action potential. 4 Both adenosine and ATP attenuated the reduction in the rate of rise of the upstroke and the amplitude of the action potential caused by the modified PSS. 5 Adenosine did not alter the noradrenaline‐induced effects on automaticity or on action potentials of normal or depressed Purkinje fibres. 6 Adenosine and ATP had electrophysiological effects on Purkinje fibres, exposed to conditions in vitro that mimic mild myocardial ischaemia, that were different from those observed on normally polarized fibres.