We used multi-exposure speckle imaging (MESI), an advanced form of laser speckle contrast imaging (LSCI), to characterize the dynamics of isoflurane anesthesia induction on cerebral vasculature and blood flow in the mouse brain. The majority of work examining the impact of anesthesia on cerebral blood flow (CBF) has been restricted to before and after measurements with limited spatial resolution. P∗∗∗<0.001, n=10 for the controls, n=10 for the 1-day group, n=13 for the 1-week group, and n=9 for the 1-month group.Īnesthetized animal models are used extensively during neurophysiological and behavioral studies despite systemic effects from anesthesia that undermine both accurate interpretation and translation to awake human physiology. The data are summarized in (d), for the amplitude of the field potentials during the 50 to 60 min time-window after HFS, expressed as % of the control amplitude. Traces over the plots are examples from a control rat and from isoflurane-exposed rats the superimposed field potentials are a baseline response and a response at 50 to 60 min after HFS (each trace is the average of 10 to 20 sweeps).
The amplitudes of three responses recorded in each min (stimulation at 0.05 Hz) were averaged, and each data point on the plot is the mean and standard error of these averages, from 9 to 13 slices. (a), (b), and (c) show the time course of changes in the amplitude of the responses after high-frequency stimulation (HFS), in control rats (black circles) and rats exposed to three sessions of 1 h isoflurane anesthesia, with a 48 h interval between sessions (open circles) LTP studies were performed at 1 day (a), 1 week (b), and 1 month (c) after the last exposure. Field potentials were evoked in the BLA by stimulation of the external capsule. Sample sizes, n=10 for the control group, n=9 for the 1-day group, and n=11 for the 1-week group.Įffects of repeated isoflurane exposures on LTP in the BLA. (c) Group data of the mean amplitudes during the 50 to 60 min time window after HFS, expressed as % of the control (baseline) amplitude.
The amplitudes of three responses recorded in each min (stimulation at 0.05 Hz) were averaged, and each data point on the plot is the mean and standard error of these averages, from 9 to 11 slices. (a) and (b) show the time course of the changes in the amplitude of the responses after high-frequency stimulation (HFS), in control rats (black circles) and rats exposed to a single, 1 h long isoflurane anesthesia (open circles), 1 day (a), and 1 week (b) after the exposure. Single isoflurane exposure for 1 h had no significant effect on the magnitude of LTP in the BLA. These pathophysiological alterations may produce emotional disturbances and impaired fear-related learning. Thus, repeated exposures to isoflurane cause a long-lasting-but not permanent-impairment of synaptic plasticity in the BLA, which could be due to increased basal GABAergic activity. Receptor-mediated IPSCs were increased at 1 day and 1 week after repeated exposures but had returned to control levels by 1 month after exposure. In contrast, after repeated isoflurane exposures, LTP was dramatically impaired at both 1 day and 1 week after the last exposure but was restored by 1 month after the exposures. Single isoflurane anesthesia had no significant effect on the magnitude of LTP. Long-term potentiation (LTP) and spontaneous GABAergic activity in the BLA were studied 1 day, 1 week, and 1 month later. Ten-week-old, male rats were administered either a single, 1 h long isoflurane (1.5%) anesthesia or three, 1 h long isoflurane exposures, separated by 48 h. In the present study, we examined whether isoflurane anesthesia produces long-term pathophysiological alterations in the basolateral amygdala (BLA), a brain region that plays a central role in emotional behavior. After surgery requiring general anesthesia, patients often experience emotional disturbances, but it is unclear if this is due to anesthetic exposure.
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