Enhanced expression of WD repeat-containing protein 35 via CaMKK/AMPK activation in bupivacaine-treated Neuro2a cells.

We previously reported that bupivacaine induces reactive oxygen species (ROS) generation, p38 mitogen-activated protein kinase (MAPK) activation and nuclear factor-kappa B activation, resulting in an increase in expression of WD repeat-containing protein 35 (WDR35) in mouse neuroblastoma Neuro2a cells. However, the identity of signaling upstream of p38 MAPK pathways to WDR35 expression remains unclear. It has been shown that AMP-activated protein kinase (AMPK) can activate p38 MAPK through diverse mechanisms. In addition, several kinases acting upstream of AMPK have been identified including Ca2+/calmodulin-dependent protein kinase kinase (CaMKK). Recent studies reported that AMPK may be involved in bupivacaine-induced cytotoxicity in Schwann cells and in human neuroblastoma SH-SY5Y cells. The present study was undertaken to test whether CaMKK and AMPK are involved in bupivacaine-induced WDR35 expression in Neuro2a cells. Our results showed that bupivacaine induced activation of AMPK and p38 MAPK in Neuro2a cells. The AMPK inhibitors, compound C and iodotubercidin, attenuated the bupivacaine-induced activation of AMPK and p38 MAPK, resulting in an inhibition of the bupivacaine-induced increase in WDR35 expression. Treatment with the CaMKK inhibitor STO-609 also attenuated the bupivacaine-induced activation of AMPK and p38 MAPK, resulting in an inhibition of the bupivacaine-induced increase in WDR35 expression. These results suggest that bupivacaine activates AMPK and p38 MAPK via CaMKK in Neuro2a cells, and that the CaMKK/AMPK/p38 MAPK pathway is involved in regulating WDR35 expression.

Enhanced expression of WD repeat-containing protein 35 via nuclear factor-kappa B activation in bupivacaine-treated Neuro2a cells.

The family of WD repeat proteins comprises a large number of proteins and is involved in a wide variety of cellular processes such as signal transduction, cell growth, proliferation, and apoptosis. Bupivacaine is a sodium channel blocker administered for local infiltration, nerve block, epidural, and intrathecal anesthesia. Recently, we reported that bupivacaine induces reactive oxygen species (ROS) generation and p38 mitogen-activated protein kinase (MAPK) activation, resulting in an increase in the expression of WD repeat-containing protein 35 (WDR35) in mouse neuroblastoma Neuro2a cells. It has been shown that ROS activate MAPK through phosphorylation, followed by activation of nuclear factor-kappa B (NF-κB) and activator protein 1 (AP-1). The present study was undertaken to test whether NF-κB and c-Jun/AP-1 are involved in bupivacaine-induced WDR35 expression in Neuro2a cells. Bupivacaine activated both NF-κB and c-Jun in Neuro2a cells. APDC, an NF-κB inhibitor, attenuated the increase in NF-κB activity and WDR35 protein expression in bupivacaine-treated Neuro2a cells. GW9662, a selective peroxisome proliferator-activated receptor-γ antagonist, enhanced the increase in NF-κB activity and WDR35 protein expression in bupivacaine-treated Neuro2a cells. In contrast, c-Jun siRNA did not inhibit the bupivacaine-induced increase in WDR35 mRNA expression. These results indicate that bupivacaine induces the activation of transcription factors NF-κB and c-Jun/AP-1 in Neuro2a cells, while activation of NF-κB is involved in bupivacaine-induced increases in WDR35 expression.

Bupivacaine-induced apoptosis independently of WDR35 expression in mouse neuroblastoma Neuro2a cells.

BACKGROUND: Bupivacaine-induced neurotoxicity has been shown to occur through apoptosis. Recently, bupivacaine was shown to elicit reactive oxygen species (ROS) production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK) in a human neuroblastoma cell line. We have reported that WDR35, a WD40-repeat protein, may mediate apoptosis through caspase-3 activation. The present study was undertaken to test whether bupivacaine induces apoptosis in mouse neuroblastoma Neuro2a cells and to determine whether ROS, p38 MAPK, and WDR35 are involved. RESULTS: Our results showed that bupivacaine induced ROS generation and p38 MAPK activation in Neuro2a cells, resulting in apoptosis. Bupivacaine also increased WDR35 expression in a dose- and time-dependent manner. Hydrogen peroxide (H(2)O(2)) also increased WDR35 expression in Neuro2a cells. Antioxidant (EUK-8) and p38 MAPK inhibitor (SB202190) treatment attenuated the increase in caspase-3 activity, cell death and WDR35 expression induced by bupivacaine or H(2)O(2). Although transfection of Neuro2a cells with WDR35 siRNA attenuated the bupivacaine- or H(2)O(2)-induced increase in expression of WDR35 mRNA and protein, in contrast to our previous studies, it did not inhibit the increase in caspase-3 activity in bupivacaine- or H(2)O(2)-treated cells. CONCLUSIONS: In summary, our results indicated that bupivacaine induced apoptosis in Neuro2a cells. Bupivacaine induced ROS generation and p38 MAPK activation, resulting in an increase in WDR35 expression, in these cells. However, the increase in WDR35 expression may not be essential for the bupivacaine-induced apoptosis in Neuro2a cells. These results may suggest the existence of another mechanism of bupivacaine-induced apoptosis independent from WDR35 expression in Neuro2a cells.

[Complications of peripheral nerve block].

BACKGROUND: Peripheral nerve block (PNB) is now widely performed in operating room by anesthesiologists. PNB is associated with multiple benefits compared to general anesthesia, but we should consider the complications of PNB. METHODS: Case reports about complications related to PNB are reviewed. Case reports related to neuraxial blocks and ophthalmologic blocks are excluded. RESULTS: 115 case reports are included. There are most reports related to the interscalene brachial plexus block when it was classified in the category of block, and most reports are related to neuropathy in terms of complications. There are only 3 reports in which ultrasound guided PNB is performed. CONCLUSIONS: Ultrasound guided PNB has become very popular now, and it has many potential advantages, such as direct visualization of nerves and anatomical structures, and direct and indirect visualization of spread of local anesthetics during injection with the possibility of repositioning the needle in case of maldistribution of local anesthetic. The half of these complications can be prevented by use of ultrasound guided PNB.

[Analysis of heart rate variability].

Heart rate variability (HRV) is a measure of the beat-to-beat variations in heart rate. It is usually calculated by analyzing a time series of beat-to-beat intervals from the ECG. Various measures of heart rate variability have been proposed, which can be subdivided into time domain, frequency domain and non-linear measures. HRV is regarded as an indicator of the activity of autonomic regulation of circulatory function. HRV has considerable potential to assess the role of autonomic nervous system fluctuations in normal healthy individuals, in patients with various cardiovascular and noncardiovascular disorders and, in patients undergoing general anesthesia. HRV studies should enhance our understanding of physiological phenomena, perioperative cardiovascular changes, the actions of medications, and disease mechanisms.

Serum concentration of lidocaine after transversus abdominis plane block.

We measured the serum concentration of lidocaine after transversus abdominis plane (TAP) block with 40 ml of 1% lidocaine in 12 patients under general anesthesia, using a fluorescence polarization immunoassay. The peak mean serum concentration of lidocaine occurred 30 min after the block (3.6 +/- 0.7 microg x ml(-1)). The highest concentration of lidocaine (5.microg x ml(-1)) was recorded 15 min after the block. These results indicate that a TAP block can potentially cause systemic toxicity of a local anesthetic. The analgesic effect of the TAP block may partially depend on the rise in serum concentration of the local anesthetic.