Effects of doxapram on myocardial repolarization in anesthetized rats

Hiroko Nomura, Yoshie Kochiyama, Tohru Irie, Masafumi Miyata, Hirofumi Kusuki, Akiko Tanaka, Hiroko Boda, Toshio Yamazaki, Tadayoshi Hata, Marina Kuriki, Mitsuru Irikura, Masatomo Takeuchi, Shunji Nagaoka

Research output: Contribution to journalArticlepeer-review


The inhibitory effects of doxapram, a respiratory accelerator, on the cardiac impulse-conducting system and myocardial repolarization time were investigated in anesthetized animals using electrocardiography. Doxapram prolonged QT and QTcE which are indicative of the myocardial repolarization time, in a dose-dependent manner in rats anesthetized by sevoflurane. However, prolongation of the atrioventricular conduction time was not observed, even at the maximum dose (10 mg/kg), and deterioration of either the QT variability index or QT variability ratio, indices of time-dependent variation in cardiac cycle and myocardial repolarization, was not observed. Doxapram prolonged the myocardial repolarization time at high doses, but maintained the physiologically valid QT/RR relationship and did not increase proarrhythmia.

Original languageEnglish
Pages (from-to)1367-1374
Number of pages8
JournalTherapeutic Research
Issue number8
Publication statusPublished - 2009

All Science Journal Classification (ASJC) codes

  • General Medicine


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