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Latency of auditory evoked potential monitoring the effects of general anesthetics on nerve fibers and synapses.

Huang B, Liang F, Zhong L, Lin M, Yang J, Yan L, Xiao J, Xiao Z - Sci Rep (2015)

Bottom Line: Auditory evoked potential (AEP) is an effective index for the effects of general anesthetics.However, it's unknown if AEP can differentiate the effects of general anesthetics on nerve fibers and synapses.Therefore, we conclude that, AEP latency is superior to amplitude for the effects of general anesthetics, ∆L monitors the effect of hypothermia on nerve fibers, and ∆I monitors a combined effect of anesthesia and hypothermia on synapses.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, PR China [2] Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, PR China.

ABSTRACT
Auditory evoked potential (AEP) is an effective index for the effects of general anesthetics. However, it's unknown if AEP can differentiate the effects of general anesthetics on nerve fibers and synapses. Presently, we investigated AEP latency and amplitude changes to different acoustic intensities during pentobarbital anesthesia. Latency more regularly changed than amplitude during anesthesia. AEP Latency monotonically decreased with acoustic intensity increase (i.e., latency-intensity curve) and could be fitted to an exponential decay equation, which showed two components, the theoretical minimum latency and stimulus-dependent delay. From the latency-intensity curves, the changes of these two components (∆L and ∆I) were extracted during anesthesia. ∆L and ∆I monitored the effect of pentobarbital on nerve fibers and synapses. Pentobarbital can induce anesthesia, and two side effects, hypoxemia and hypothermia. The hypoxemia was not related with ∆L and ∆I. However, ∆L was changed by the hypothermia, whereas ∆I was changed by the hypothermia and anesthesia. Therefore, we conclude that, AEP latency is superior to amplitude for the effects of general anesthetics, ∆L monitors the effect of hypothermia on nerve fibers, and ∆I monitors a combined effect of anesthesia and hypothermia on synapses. When eliminating the temperature factor, ∆I monitors the anesthesia effect on synapses.

No MeSH data available.


Related in: MedlinePlus

Changes in AEP latency and amplitude to different acoustic intensities.(a,b) Changes in latency and amplitude to 40–90 dB acoustic stimuli with anesthesia time, hereafter, latency- and amplitude-time curves. (c and d) R2 values and absolute values of residuals obtained by fitting normalized latency- and amplitude-time curves (computing methods were similar to those in Fig. 2) (*P < 0.05, **P < 0.01, 2 Independent Samples Tests).
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f3: Changes in AEP latency and amplitude to different acoustic intensities.(a,b) Changes in latency and amplitude to 40–90 dB acoustic stimuli with anesthesia time, hereafter, latency- and amplitude-time curves. (c and d) R2 values and absolute values of residuals obtained by fitting normalized latency- and amplitude-time curves (computing methods were similar to those in Fig. 2) (*P < 0.05, **P < 0.01, 2 Independent Samples Tests).

Mentions: Although AEP L80 exhibited more regular and less variable changes than A80, whether AEPs to acoustic stimuli at other intensities undergo similar changes during anesthesia is still unclear. Therefore, we applied multiple acoustic intensities other than 80 dB to the subjects. The latency to each acoustic intensity (No. 18 mouse (M20110417)) showed an initial increase followed by a gradual decrease during anesthesia (Fig. 3a). The maximal latency to each acoustic intensity always occurred in the same recording session (Fig. 3a, the vertical green line). The latency change ranges (the maximal latency—the minimal latency) to different acoustic intensities were, respectively, 13.475, 12.344, 8.935, 6.23, 6.147 and 5.41 ms from 40 dB to 90 dB at 10 dB intervals, and were negatively correlated with the acoustic intensity. These results indicated that AEP latencies to low intensity acoustic stimuli were more suitable for reflecting the effects of general anesthetics.


Latency of auditory evoked potential monitoring the effects of general anesthetics on nerve fibers and synapses.

Huang B, Liang F, Zhong L, Lin M, Yang J, Yan L, Xiao J, Xiao Z - Sci Rep (2015)

Changes in AEP latency and amplitude to different acoustic intensities.(a,b) Changes in latency and amplitude to 40–90 dB acoustic stimuli with anesthesia time, hereafter, latency- and amplitude-time curves. (c and d) R2 values and absolute values of residuals obtained by fitting normalized latency- and amplitude-time curves (computing methods were similar to those in Fig. 2) (*P < 0.05, **P < 0.01, 2 Independent Samples Tests).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526847&req=5

f3: Changes in AEP latency and amplitude to different acoustic intensities.(a,b) Changes in latency and amplitude to 40–90 dB acoustic stimuli with anesthesia time, hereafter, latency- and amplitude-time curves. (c and d) R2 values and absolute values of residuals obtained by fitting normalized latency- and amplitude-time curves (computing methods were similar to those in Fig. 2) (*P < 0.05, **P < 0.01, 2 Independent Samples Tests).
Mentions: Although AEP L80 exhibited more regular and less variable changes than A80, whether AEPs to acoustic stimuli at other intensities undergo similar changes during anesthesia is still unclear. Therefore, we applied multiple acoustic intensities other than 80 dB to the subjects. The latency to each acoustic intensity (No. 18 mouse (M20110417)) showed an initial increase followed by a gradual decrease during anesthesia (Fig. 3a). The maximal latency to each acoustic intensity always occurred in the same recording session (Fig. 3a, the vertical green line). The latency change ranges (the maximal latency—the minimal latency) to different acoustic intensities were, respectively, 13.475, 12.344, 8.935, 6.23, 6.147 and 5.41 ms from 40 dB to 90 dB at 10 dB intervals, and were negatively correlated with the acoustic intensity. These results indicated that AEP latencies to low intensity acoustic stimuli were more suitable for reflecting the effects of general anesthetics.

Bottom Line: Auditory evoked potential (AEP) is an effective index for the effects of general anesthetics.However, it's unknown if AEP can differentiate the effects of general anesthetics on nerve fibers and synapses.Therefore, we conclude that, AEP latency is superior to amplitude for the effects of general anesthetics, ∆L monitors the effect of hypothermia on nerve fibers, and ∆I monitors a combined effect of anesthesia and hypothermia on synapses.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, PR China [2] Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, PR China.

ABSTRACT
Auditory evoked potential (AEP) is an effective index for the effects of general anesthetics. However, it's unknown if AEP can differentiate the effects of general anesthetics on nerve fibers and synapses. Presently, we investigated AEP latency and amplitude changes to different acoustic intensities during pentobarbital anesthesia. Latency more regularly changed than amplitude during anesthesia. AEP Latency monotonically decreased with acoustic intensity increase (i.e., latency-intensity curve) and could be fitted to an exponential decay equation, which showed two components, the theoretical minimum latency and stimulus-dependent delay. From the latency-intensity curves, the changes of these two components (∆L and ∆I) were extracted during anesthesia. ∆L and ∆I monitored the effect of pentobarbital on nerve fibers and synapses. Pentobarbital can induce anesthesia, and two side effects, hypoxemia and hypothermia. The hypoxemia was not related with ∆L and ∆I. However, ∆L was changed by the hypothermia, whereas ∆I was changed by the hypothermia and anesthesia. Therefore, we conclude that, AEP latency is superior to amplitude for the effects of general anesthetics, ∆L monitors the effect of hypothermia on nerve fibers, and ∆I monitors a combined effect of anesthesia and hypothermia on synapses. When eliminating the temperature factor, ∆I monitors the anesthesia effect on synapses.

No MeSH data available.


Related in: MedlinePlus