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Updated: Sep 26, 2026

In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model
Published on: October 27, 2020
Effects of moderate hypothermia on norepinephrine release evoked by ouabain, tyramine and cyanide
Hirotoshi Kitagawa1, Toji Yamazaki, Tsuyoshi Akiyama
1Department of Anesthesia, Nagahama City Hospital, Nagahama, Japan. hirotosi@belle.shiga-med.ac.jp
Abstract:
Using the dialysis technique, we examined the effect of moderate hypothermia on the norepinephrine efflux evoked by ouabain, tyramine and cyanide in anesthetized cats. Dialysis probes were implanted in the left ventricular myocardium, and we measured the dialysate norepinephrine levels as an indicator of norepinephrine output at the cardiac sympathetic nerve endings. Through the dialysis probe, locally applied ouabain, tyramine and cyanide induced the norepinephrine efflux. The addition of desipramine (neuronal norepinephrine transport blocker, 100 microM) suppressed the norepinephrine efflux evoked by ouabain, tyramine and cyanide. This finding suggests that pharmacological agent-induced norepinephrine efflux was due to carrier-mediated outward norepinephrine transport. Moderate hypothermia (27.4 +/- 0.2 degrees C) caused suppression of the norepinephrine efflux evoked by ouabain, tyramine and cyanide. We conclude that moderate hypothermia suppresses the non-exocytotic norepinephrine release evoked by ouabain, tyramine and cyanide.
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