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Published on: July 16, 2009
Prolonged exposure to ketamine increases neurodegeneration in the developing monkey brain
Xiaoju Zou1, Tucker A Patterson, Rebecca L Divine
1Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.
Summary
Ketamine anesthesia up to 3 hours did not cause significant neurotoxicity in developing brains. However, longer exposures of 9 or 24 hours led to increased neuronal cell death in the frontal cortex, indicating a critical duration threshold for pediatric anesthesia safety.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Anesthesiology
Background:
- Ketamine is a common pediatric anesthetic.
- Concerns exist regarding ketamine's potential neurotoxicity in developing brains.
- Mechanisms and susceptibility to ketamine-induced neuronal damage are not fully understood.
Purpose of the Study:
- To determine the duration threshold of ketamine anesthesia below which neurodegeneration is not significant.
- To investigate the impact of varying ketamine exposure durations on neuronal cell death in infant brains.
Main Methods:
- Newborn rhesus monkeys (postnatal day 5-6) received ketamine intravenously for 3, 9, or 24 hours.
- Brain tissue was analyzed using silver and Fluoro-Jade C stains and caspase-3 immunostaining.
- Neuronal cell death was assessed in various brain regions, including the frontal cortex, hippocampus, and thalamus.
Main Results:
- Ketamine exposure for 3 hours did not result in significant neurotoxic effects.
- Anesthesia durations of 9 and 24 hours significantly increased neuronal cell death in the frontal cortex (layers II and III).
- No significant differences in neuronal cell death were observed in other brain areas like the hippocampus and thalamus across all exposure durations.
Conclusions:
- Ketamine administration up to 3 hours appears safe regarding neurotoxicity in developing brains.
- Anesthetic durations of 9 hours or longer are associated with significant frontal cortex neuronal cell death.
- The threshold for ketamine-induced neurotoxicity in infant brains lies between 3 and 9 hours of exposure.
