These results suggest that EAAT3 knockout mice have significant cognitive impairment. Isoflurane may not significantly affect the cognition of wild-type and EAAT3 knockout mice in a delayed phase after isoflurane exposure.

Hippocampus-dependent learning and memory are associated with trafficking of excitatory amino acid transporter type 3 (EAAT3) to the plasma membrane. To assess whether this trafficking is an intrinsic component of the biochemical responses underlying learning and memory, 7- to 9-week old male EAAT3 knockout mice and CD-1 wild-type mice were subjected to fear conditioning. Their hippocampal CA1 regions, amygdalae and entorhinal cortices were harvested before, or 30 min or 3 h after the fear conditioning stimulation. We found that EAAT3 knockout mice had worse contextual and tone-related learning and memory than did the wild-type mice. The expression of EAAT3, glutamate receptor (GluR)1 and GluR2 in the plasma membrane and of phospho-GluR1 (at Ser 831) and phospho-CaMKII in the hippocampus of the wild-type mice was increased at 30 min after the fear conditioning stimulation. Similar biochemical changes occurred in the amygdala. Fear conditioning also increased the expression of c-Fos and activity-regulated cytoskeleton-associated protein (Arc) in the CA1 regions and of Arc in the entorhinal cortices of the wild-type mice. These biochemical responses were attenuated in the EAAT3 knockout mice. These results suggest that EAAT3 plays a critical role in learning and memory. Our results also provide initial evidence that EAAT3 may have receptor-like functions to participate in the biochemical reactions underlying learning and memory.

Background: We performed this prospective double-blind randomized controlled trial to identify the effect of a preoperative prophylactic transdermal scopolamine (TDS) patch on postoperative nausea and vomiting (PONV) after retromastoid craniectomy with microvascular decompression (RMC-MVD). Methods: We recruited 38 patients undergoing RMC-MVD and randomized them into two groups: the TDS group (n = 19, application of the TDS patch) and placebo group (n = 19, application of a sham patch). Nausea (as a self-reported 100-mm visual analog scale (VAS) score; range, 0 (no nausea) to 10 (worst nausea)), vomiting, and the use of antiemetics were the primary endpoints. Results: There was no significant difference in terms of the incidence of PONV (73.7% in the TDS group and 78.9% in the placebo group; p = 1.00) between the groups. However, the mean nausea VAS score was significantly different at arrival to the general ward (0.93 ± 1.71 in the TDS group vs. 2.52 ± 2.85 in the placebo group; p = 0.046), and throughout the study period (0.03 ± 0.07 in the TDS group vs. 0.44 ± 0.71 in the placebo group; p = 0.029). Rescue antiemetics were more frequently used in the placebo group than in the TDS group (9 (47.4%) vs. 2 (10.5%), respectively; p = 0.029). The mean number of antiemetics used throughout the study period was significantly higher in the placebo group than in the TDS group (1.37 ± 2.19 vs. 0.16 ± 0.50, respectively; p = 0.029). Conclusions: The preoperative prophylactic use of a TDS patch was safe and effective in the management of PONV after RMC-MVD in terms of the severity of PONV and the use of rescue antiemetics.