Dose-dependent effect of isoflurane on regional cerebral blood flow in anesthetized macaque monkeys

Abstract

The dose-dependent effect of isoflurane on regional CBF of cortical and subcortical structures in anesthetized macaque monkeys was investigated with the Continuous ASL MRI technique. High concentration of isoflurane resulted in global CBF increase and blood pressure decrease. Evident CBF change was observed in the subcortical structures. Specifically, CBF in thalamus and cerebellum was increased about 39% and 55% when isoflurane concentration was changed from 0.75% to 1.5%, respectively. Also, those regional CBF changes correlated linearly with isoflurane inspiratory concentrations, indicating impaired CBF autoregulation in these structures. In contrast, no obvious CBF changes were observed in anterior cingulated cortex, motor cortex, medial prefrontal cortex, and caudate. The results demonstrate that, under the 0.75–1.5% isoflurane maintenance doses, the CBF auto-regulation is well preserved in the cerebral cortical regions and caudate, but impaired in thalamus and cerebellum, indicating disturbed CBF-metabolism coupling and functional response in specific subcortical regions of anesthetized macaque monkeys.

Effects of Long-Duration Administration of 1% Isoflurane on Resting Cerebral Blood Flow and Default Mode Network in Macaque Monkeys

“…CBF and cerebral metabolism can be altered by sedatives, analgesics, and anesthetics dramatically and the effects vary substantially from one drug to another (Van Aken and Van Hemelrijck, 1991;Werner, 1995). Isoflurane has strong dose-dependent effects on CBF as demonstrated in prior studies of anesthetized macaques or baboons (Li et al, 2013(Li et al, , 2014Van Aken et al, 1986). The duration effects of isoflurane on CBF have also been previously examined in anesthetized dogs (McPherson and Traystman, 1988) and goats (Albrecht et al, 1983), and monkeys (McPherson et al, 1994), but the conclusions remain controversial.…”

“…Lactated ringer's solution was administered intravenously to prevent dehydration during scanning. The physiological parameters were recorded and maintained in normal ranges (Li et al, 2013). All procedures followed the protocols approved by the Institutional Animal Care and Use Committee (IACUC) of Emory University in accordance with the NIH Guide for Care and Use of Laboratory Animals.…”

“…CBF data analyses were performed by using home-built Matlab scripts (MathWorks, MA) and Stimulate software (www.cmrr.umn.edu/stimulate) (Li et al, 2013). The bilateral caudate, putamen, globus pallidus, anterior cingulated cortex (ACC), posterior cingulate cortex (PCC), thalamus, cerebellum, white matter (WM), grey matter (GM), and cortical and subcortical cortex were selected as regions of interest (ROIs) to acquire averaged CBF values (Fig.…”

“…It has been demonstrated that isoflurane has dosedependent effects on physiology (such as CBF, blood pressure, heart rate, cerebral metabolism, systemic vascular resistance) of monkeys and humans (Kato et al, 1992;Li et al, 2013Li et al, , 2014Lorenz et al, 2001;Reinstrup et al, 1995). In addition, neurobehavioral disturbances and cognitive decline have been reported in patients post-anesthesia (Block et al, 2012;Flick et al, 2011;Sprung et al, 2012;Wilder et al, 2009).…”

A Longitudinal Magnetization Transfer Imaging Evaluation of Brain Injury in a Macaque Model of NeuroAIDS

“…Et-CO 2 , inhaled CO 2 , O 2 saturation, blood pressure, heart rate, respiration rate, and body temperature were monitored continuously and maintained in the normal ranges. 22 The MT images (Fig. 1, middle row) were acquired using a customdesigned EPI sequence with the following parameters: TR/ TE = 3,810 ms/18 ms, FOV = 96 · 96 mm, data matrix = 64 · 64, slice thickness = 2.2 mm, 60 measurements (30-pair images with/without presaturation RF irradiation for average purpose), and 16 slices were acquired.…”