Effect of high dose isoflurane on cerebral blood flow in macaque monkeys

Area of Science:

• Neuroscience
• Anesthesiology
• Medical Imaging

Background:

• Isoflurane is a common anesthetic agent used in both human and non-human primate neuroimaging.
• Understanding its effects on cerebral blood flow (CBF) is crucial for accurate interpretation of brain activity.
• Previous studies have shown variable effects of anesthetics on CBF, necessitating further investigation into high-dose effects.

Purpose of the Study:

• To investigate the impact of high-dose isoflurane on regional cerebral blood flow (CBF) in adult macaque monkeys.
• To determine if CBF changes are dose-dependent and region-specific.
• To assess the implications of these findings for neuroimaging studies.

Main Methods:

• Utilized pseudo continuous arterial-spin-labeling (pCASL) Magnetic Resonance Imaging (MRI) technique.
• Administered isoflurane at concentrations ranging from 1% to 2% in adult macaque monkeys.
• Analyzed global, cortical, and subcortical CBF changes in response to varying isoflurane doses.

Main Results:

• A high concentration (2%) of isoflurane significantly increased mean CBF globally, in cortical, and subcortical regions.
• Regional CBF increased in all subcortical structures and most cortical areas, including the motor cortex and anterior cingulate cortex.
• Changes in regional CBF showed a linear correlation with increasing isoflurane concentrations, except in the medial prefrontal cortex.

Conclusions:

• High-dose isoflurane (2%) induces region-specific abnormal increases in CBF in adult macaque monkeys.
• These CBF alterations suggest potential impacts on brain functionality in affected structures.
• Findings emphasize the need to consider isoflurane's effects on CBF in human and non-human primate neuroimaging studies.