Effects of diltiazem and noradrenaline on extracellular potassium changes in the globally ischaemic rat heart
| Autor: | Yoshikazu Tsuruhara, Kazuhiro Kurisu, Atsuo Mitani, Kazuhiko Kinoshita, Masato Sakamoto, Kiyotaka Fukamachi, Fumio Fukumura, Kouichi Tokunaga, Atsuhiro Nakashima |
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| Rok vydání: | 1992 |
| Předmět: |
medicine.medical_specialty
Physiology Potassium Myocardial Ischemia chemistry.chemical_element Calcium Diltiazem Norepinephrine Valinomycin chemistry.chemical_compound Adenosine Triphosphate Adenine nucleotide Coronary Circulation Physiology (medical) Internal medicine medicine Animals Ventricular Function Rats Wistar business.industry Antagonist Coronary Vessels Rats Electrophysiology Endocrinology medicine.anatomical_structure chemistry Ventricle Anesthesia Catecholamine Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Cardiovascular Research. 26:1040-1045 |
| ISSN: | 0008-6363 |
| Popis: | Objective: The aim was to investigate the effects of a calcium antagonist (diltiazem) and a catecholamine (noradrenaline) on extracellular potassium accumulation during global ischaemia. Methods: Extracellular potassium concentration ([K+]e) was measured during 30 min global ischaemia in the isolated rat heart using a valinomycin potassium sensitive electrode. Contracture development during ischaemia was measured throughout with an intraventricular balloon inserted into the left ventricle and myocardial adenine nucleotides were measured in separate series of hearts. Results: In control hearts, [K+]e showed a characteristic triphasic change during 30 min global ischaemia. This consisted of an early rising phase followed by a transient falling phase after the initial peak of [K+]e, and then a late rising phase. Diltiazem suppressed the rate of rise of [K+]e during early ischaemia, but extended the time course of the early [K+]e rise with the higher dose, abolishing the transient falling phase of [K+]e. During late ischaemia, the rise in [K+]e was attenuated by diltiazem. Noradrenaline also suppressed the early extracellular potassium accumulation, but in contrast to diltiazem, hastened the time course of the late [K+]e rise. Conclusions: Although diltiazem suppresses the early potassium loss during ischaemia as previously described, the drug also decreases the [K+]e fall by some as yet unknown mechanism, so that the [K+]e level becomes higher than control during the falling phase. Cardiovascular Research 1992; 26 :1040-1045 |
| Databáze: | OpenAIRE |
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