Isoflurane enhances the expression of cytochrome C by facilitation of NMDA receptor in developing rat hippocampal neurons in vitro

NR2B receptor- and calpain-mediated KCC2 cleavage resulted in cognitive deficiency exposure to isoflurane

BACKGROUND

During brain development, volatile anesthetic can rapidly interfere with physiologic patterns of dendritic development and synaptogenesis and impair the formation of precise neuronal circuits. KCC2 plays vital roles in spine development and synaptogenesis through its Cl- transport function and structural interactions with the spine cytoskeleton protein 4.1 N. The aim of this study was to dissect the mechanism of volatile anesthetics, which impair dendritic development and synaptogenesis via mediation of KCC2 cleavage.

METHODS

Westernblotting was employed to assess the expression change of NR2B, NR2A, calpain-1, calpain-2, KCC2, and 4.1 N protein of rat (PND 5). Co-immunoprecipitation was applied to demonstrate the interaction between KCC2 and 4.1 N protein. Long-term cognitive deficiency was assessed by MWM. Lentivirus-calpain-2 was administered by hippocampus stereotaxic injection.

RESULTS

There was a significant increase in the level of NR2B instead of NR2A exposure to isoflurane. Calpain-2 was excessively activated via NR2B after 6 h of isoflurane exposure. The expression of plasmalemmal KCC2 and 4.1 N protein was significantly decreased treated with isoflurane. The isoflurane group showed longer traveled distance, prolonged escape latency, less time spent in the target quadrant, and decreased platform crossings. Pretreatment with ifenprodil and downregulated calpain-2 expression significantly alleviated these neurotoxicity responses and cognitive deficiency after isoflurane exposure.

CONCLUSIONS

A significant increase in NR2B, excessive activation of calpain-2 and increased cleavage of plasmalemmal KCC2, are involved in isoflurane-induced neurotoxicity and long-term cognitive deficiency. Blocking NR2B and calpain-2 activity significantly attenuated these responses. The KCC2 cleavage mediated by NR2B and calpain-2 is a major determinant of isoflurane-induced long-term cognitive deficiency.

Sevoflurane addiction due to workplace exposure: A case report and literature review

RATIONALE

Anesthesiologists have a well-known increased risk of substance abuse. High-concentration of inhalation anesthetics in exhaled air of operating room personnel is detected. such secondhand exposure produces neurobiological sensitization to the reinforcing effects of inhalation anesthetics.

PATIENT CONCERNS

An addictive young male anesthesiologist who was long-term abuse with sevoflurane after 4 years occupational exposure. A 28-year-old anesthesiologist on duty was found deeply sleep in the locker room and coved his nose with Gauze with high-concentration of sevoflurane. He was found addiction to sevoflurane second time. Several life-threatening incidents occurred including severe aspiration pneumonia. No other addiction was found in his history before he became severely dependent on sevoflurane.

DIAGNOSES

A visual analog scale was employed to assess the severity of craving for sevoflurane and the Benzodiazepine Withdrawal Symptom Scale (BWSQ2)-scale was used to assess sevoflurane withdrawal syndrome(WS).

INTERVENTIONS

First time an opened original sevoflurane container filled with water instead of sevoflurane was handed out for a minute in order to elicit craving and withdrawal symptom in five therapeutic single-sessions. Second time an opened original sevoflurane container filled with sevoflurane instead of water was used as his powerful cur-stimulus and also was handed out for a minute.

OUTCOMES

After professional therapy and continuous surveillance he was rehabilitation and back to work. However, after three weeks he became addiction to sevoflurane again. He showed very sensitive to sevoflurane and switched to other career.

LESSONS

This case emphasizes that secondhand exposure to inhalation anesthetics may be dangerous and increase the life-threatening professional risk to anesthesiologists, although identification of the responsible factor remains difficult. However, the safety of operating room staff should be aroused wide-spread social concern.