THE HAMSTER HEART IS RESISTANT TO CALCIUM PARADOX

Reintroduction of Ca2+or modification of internal Ca2+stores by caffeine results in widespread irreversible injury. The adult golden hamster, however, is immune to such insult and the present report investigates the phenomenon. Isolated Langendorff perfused hamster and rat heart were subjected to 15...

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Bibliographic Details
Published in:Pharmacological research 2000-04, Vol.41 (4), p.475-481, Article 475
Main Authors: RAY, MADHUR, SRIVASTAVA, SHEKHAR, MAITRA, SHYAMAL CHANDRA, DUBEY, MANGAL PRASAD
Format: Article
Language:English
Subjects:
Animals
Caffeine - pharmacology
Calcium - deficiency
Calcium - metabolism
Cricetinae
electron microscopy, gap junctions, myocytes, hamster heart, calcium paradox
Heart - drug effects
In Vitro Techniques
Male
Mesocricetus
Microscopy, Electron
Myocardial Contraction - drug effects
Myocardial Reperfusion Injury - metabolism
Myocardial Reperfusion Injury - pathology
Myocardium - cytology
Myocardium - metabolism
Myocardium - pathology
Papillary Muscles - drug effects
Phosphodiesterase Inhibitors - pharmacology
Rats
Rats, Sprague-Dawley
Sarcoplasmic Reticulum - drug effects
Sarcoplasmic Reticulum - metabolism
Tissue Fixation
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Summary:Reintroduction of Ca2+or modification of internal Ca2+stores by caffeine results in widespread irreversible injury. The adult golden hamster, however, is immune to such insult and the present report investigates the phenomenon. Isolated Langendorff perfused hamster and rat heart were subjected to 15 min Ca2+-free perfusion followed by 30 min of Ca2+perfusion at 37°C. Caffeine was introduced during Ca2+-free perfusion in a number of experiments. Papillary muscles were processed for the ultra-structural study. The hamster heart did not exhibit the calcium paradox state whereas rat heart did. Hamster heart treated with caffeine either throughout or 5 min after starting Ca2+-free perfusion showed 70%±8 or 65%±8.42 recovery, respectively, when Ca2+reperfusion was performed. Ultrastructure of muscle from both groups showed relaxed myocytes with slight disorientation of the sarcomere register. This disorientation was not seen in hamster hearts undergoing the conventional calcium paradox protocol. The hamster cardiac muscle is remarkably tolerant to [Ca2+]i loading either induced by Ca2+reperfusion or caffeine-induced sarcoplasmic reticulum Ca2+release. Structural and functional characterization of Ca2+depletion and repletion in the hamster heart have been discussed.
ISSN:1043-6618
1096-1186
DOI:10.1006/phrs.1999.0607