Riluzole attenuates excitatory amino acid transporter type 3 activity in Xenopus oocytes via protein kinase C inhibition.

This study aimed to evaluate the effect of riluzole on the activity of excitatory amino acid transporter type 3 (EAAT3), a neuronal glutamate transporter, and to investigate the role of protein kinase C (PKC) in this effect. EAAT3 expression was induced in Xenopus oocytes by injecting EAAT3 mRNA. Using the two-electrode voltage clamping method, membrane currents were recorded before, during, and after applying l-glutamate (30 µM) in the absence and presence of prior incubation with riluzole (0.3-100 µM). To study the effect of PKC on the riluzole-induced change in EAAT3 activity, oocytes were preincubated with 100 µM phorbol-12-myristate-13-acetate (PMA), a PKC activator, or PKC inhibitors (2 µM staurosporine and 100 µM chelerythrine) before the recording. Responses were quantified by integrating current traces and are reported in microCoulombs (µC). Riluzole reduced EAAT3 activity in a concentration-dependent manner (0.3-100 µM). Treatment of oocytes with PMA significantly increased the baseline and riluzole-reduced EAAT activity (P<0.05). In addition, treatment of oocytes with PKC inhibitors reduced basal transporter currents, but did not show a further significant decrease in the riluzole-reduced EAAT3 activity. These results suggest that riluzole reduces EAAT3 activity through PKC inhibition.

Use of a neck brace minimizes double-lumen tube displacement during patient positioning.

PURPOSE: When patients are moved from the supine to the lateral decubitus position, the double-lumen endobronchial tube (DLT) is often displaced. The aim of this study was to determine whether a DLT is displaced when there are no movements of the head and neck. METHODS: One hundred patients scheduled for elective thoracic surgery were randomly divided into control and brace groups. Only a left-sided DLT was used during the study. All patients in the brace group wore a neck collar before the positional change. Using a fibreoptic bronchoscope, the distance from the tracheal opening to the main carina and from the bronchial opening to the bronchial carina was measured in the supine and lateral decubitus positions. RESULTS: Displacement of the DLT (mean +/- SD) during a change from the supine to the lateral decubitus position was greater in the control group (6.3 +/- 5.5 mm in the trachea; 2.4 +/- 3.6 mm in the bronchus) than in the brace group (2.2 +/- 3.9 mm in the trachea; 0.6 +/- 3.1 mm in the bronchus); (P < 0.001). The incidence of clinically significant displacement, greater than 5 mm from the initial correct position, was higher in the control group than in the brace group (48% vs 12%, P < 0.001). CONCLUSION: By restricting head and neck movements with a neck brace, the DLT displacement could be minimized while positioning patients for thoracotomy. The main cause of the DLT displacement during lateral positioning appears to be related to movement of the head and neck.