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Graduate School of Biomedical Sciences

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Anesthesiology | Neuroscience and Neurobiology | Pharmacology


D-amphetamine induces emergence from sevoflurane and propofol anesthesia in rats. Dexmedetomidine is an alpha2-adrenoreceptor agonist that is commonly used for procedural sedation, whereas ketamine is an anesthetic that acts primarily by inhibiting NMDA-type glutamate receptors. These drugs have different molecular mechanisms of action from propofol and volatile anesthetics that enhance inhibitory neurotransmission mediated by GABAA receptors. In this study, we tested the hypothesis that d-amphetamine accelerates recovery of consciousness after dexmedetomidine and ketamine. Sixteen rats (Eight males, eight females) were used in a randomized, blinded, crossover experimental design and all drugs were administered intravenously. Six additional rats with pre-implanted electrodes in the prefrontal cortex (PFC) were used to analyze changes in neurophysiology. After dexmedetomidine, d-amphetamine dramatically decreased mean time to emergence compared to saline (saline:112.8 +/- 37.2 min; d-amphetamine:1.8 +/- 0.6 min, p < 0.0001). This arousal effect was abolished by pre-administration of the D1/D5 dopamine receptor antagonist, SCH-23390. After ketamine, d-amphetamine did not significantly accelerate time to emergence compared to saline (saline:19.7 +/- 18.0 min; d-amphetamine:20.3 +/- 16.5 min, p = 1.00). Prefrontal cortex local field potential recordings revealed that d-amphetamine broadly decreased spectral power at frequencies < 25 Hz and restored an awake-like pattern after dexmedetomidine. However, d-amphetamine did not produce significant spectral changes after ketamine. The duration of unconsciousness was significantly longer in females for both dexmedetomidine and ketamine. In conclusion, d-amphetamine rapidly restores consciousness following dexmedetomidine, but not ketamine. Dexmedetomidine reversal by d-amphetamine is inhibited by SCH-23390, suggesting that the arousal effect is mediated by D1 and/or D5 receptors. These findings suggest that d-amphetamine may be clinically useful as a reversal agent for dexmedetomidine.


d-amphetamine, dexmedetomidine, emergence from anesthesia, ketamine, prefrontal cortex

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Copyright © 2021 Kato, Zhang, Mallari, Moody, Vincent, Melonakos, Siegmann, Nehs, Houle, Akeju and Solt. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

DOI of Published Version



Kato R, Zhang ER, Mallari OG, Moody OA, Vincent KF, Melonakos ED, Siegmann MJ, Nehs CJ, Houle TT, Akeju O, Solt K. D-Amphetamine Rapidly Reverses Dexmedetomidine-Induced Unconsciousness in Rats. Front Pharmacol. 2021 May 18;12:668285. doi: 10.3389/fphar.2021.668285. PMID: 34084141; PMCID: PMC8167047. Link to article on publisher's site

Journal/Book/Conference Title

Frontiers in pharmacology

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.