Impaired spatial learning and memory after sevoflurane-nitrous oxide anesthesia in aged rats is associated with down-regulated cAMP/CREB signaling.

Neurocognitive deficits arising from anesthetic exposure have recently been debated, while studies have shown that the phosphorylation of cyclic AMP response element-binding protein (CREB) in the hippocampus is critical for long-term memory. To better understand the neural effects of inhalational anesthetics, we studied the behavioral and biochemical changes in aged rats that were exposed to sevoflurane (Sev) and nitrous oxide (N2O) for 4 h. Eighteen-month-old rats were randomly assigned to receive 1.3% sevoflurane and 50% nitrous oxide/50% oxygen or 50% oxygen for 4 h. Spatial learning and memory were tested with the Morris water maze 48 h after exposure, and the results showed that sevoflurane-nitrous oxide exposure induced a significant deficit in spatial learning acquisition and memory retention. Experiments revealed that the cAMP and pCREB levels in the dorsal hippocampus were decreased in rats with anesthetic exposure in comparison with control rats 48 h after anesthesia as well as 15 min after the probe trial, but there were no significant differences in CREB expression. Besides these, the current study also found the DG neurogenesis significantly decreased as well as neuronal loss and neuronal apoptosis increased in the hippocampus of rats exposed to Sev+N2O. The current study demonstrated that down-regulation of cAMP/CREB signaling, decrease of CREB-dependent neurogenesis and neuronal survival in the hippocampus contributed to the neurotoxicity and cognitive dysfunction induced by general anesthesia with sevoflurane-nitrous oxide.

[Evaluation of a portable device based on peripheral arterial tone in the detection of obstructive sleep apnea].

OBJECTIVE: To assess the accuracy of a wrist-worn device (Watch-PAT 200) in the diagnosis of obstructive sleep apnea syndrome (OSAHS). METHODS: Forty-three adult subjects with suspected OSAHS simultaneously had a standard in-laboratory polysomnogram (PSG) and wore the Watch-PAT 200 during a full-night recording. PSG sleep and respiratory events were scored according to standard criteria. The PSG recordings were blindly manually analyzed, while Watch-PAT data were scored automatically based on the algorithm developed previously. RESULTS: The mean age of the subjects was (42.2 ± 12.2) years (x(-) ± s), and mean body mass index was (28.0 ± 3.9) kg/m(2). Mean PSG apnea hypopnea index (AHI) was (34.9 ± 29.9) events per hour, and mean PAT-AHI was (36.0 ± 29.2) events per hour. There was a significant correlation between PAT AHI and AHI by PSG (r = 0.931, P < 0.01). A Bland-Altman plot of PAT AHI and PSG AHI was also used to assess the accuracy of Watch-PAT 200. At lower levels of AHI, PAT tended to overestimate disease severity, while at higher levels of AHI, Watch-PAT underestimated severity. To assess sensitivity and specificity of Watch-PAT, constructed receiver operator characteristic curves using a variety of AHI threshold values (5, 15 and 30 events per hour). For AHI ≥ 5 events per hour as threshold value, the Watch-PAT diagnosing rate was 93%, and sensitivity as well as specificity were 94.7% and 80.0%. The misdiagnosis rate and missed diagnosis rate were 20.0% and 5.3%. Optimal combinations of sensitivity and specificity for the AHI threshold values (15 and 30 events per hour) were 82.6% and 100.0%, 95.0% and 95.7% respectively. CONCLUSION: The Watch-PAT 200 may offer an accurate, robust, and reliable ambulatory method for the detection of OSAHS, with minimal patient discomfort.