Effects of RMF on BKCa and Kv channels in basilar arterial smooth­muscle cells of SHR.

The current study observed the effects and investigated the mechanism of remifentanil (RMF) on the isolated cerebral basilar arteries of spontaneously hypertensive rats (SHR) and Wistar­Kyoto (WKY) rats. A pressure myograph system was used to observe and compare the effects of different concentrations of RMF (10­10­10­5 mol/l) on the diameter changes of freshly isolated cerebral basilar arteries, which have been pre­shrunk by phenylephrine (PE), an endothelium­independent vasoconstrictor. Vascular smooth­muscle cells of the cerebral basilar artery (BASMCs) were freshly obtained via enzymolysis. BKCa (large­conductance calcium­activated potassium channels) current (IBKCa) and Kv (voltage­gated potassium channels) current (IKv) were recorded using a whole­cell patch­clamp technique. The changes in IBKCa and IKv produced by different concentrations of RMF (10­10 to 10­5 mol/l) on the two types of rats with the holding potential of ­40 mV were observed and compared. The cerebral basilar arteries of the SHR and WKY rats were relaxed by RMF in a concentration-dependent manner (P<0.05; n=5). At the same concentration, the diastolic effect of RMF on SHR was weaker than that observed in WKY rats (P<0.05, n=5). When the rats were pre­perfused with 10­3 mol/l of the BKCa channel blocker tetraethylammonium (TEA), the diastolic amplitudes of RMF in SHR and WKY rats were decreased, and the fitting curves shifted down (P<0.05; n=7 and 6, respectively). However, no statistically significant difference was observed with 10­3 mol/l of the Kv channel blocker 4­aminopyridine (4­AP; n=6 and 9, respectively; P>0.05). Outward currents were increased by RMF in both BASMCs of SHR and WKY rats in a voltage­ and dose­dependent manner (P<0.05; n=6). At the same concentration, the effect of RMF on the outward currents in BASMCs of WKY rats was stronger than that on SHR (P<0.05; n=6). The enhancing effect of RMF can be partially blocked by either 10­3 mol/l TEA (P<0.05; n=6) or 10­3 mol/l 4­AP (P<0.05 or 0.01; n=6 and 9, respectively) however can be totally blocked by the mixture of TEA and 4­AP (P<0.05, n=7). RMF served a diastolic role in the cerebral basilar arteries of rats in a dose­dependent manner, likely by activating the BKCa and Kv channels. However, SHR demonstrated a less pronounced diastolic reaction to RMF than that observed in WKY rats.

[Effects of sleep deprivation on the intelligence structure of school-age children in Changsha, China].

OBJECTIVE: To investigate the effects of sleep deprivation on intelligence development in primary school students. METHODS: Between June 2009 and April 2010, 316 grade 5 students aged 10-11 years were selected from four primary schools in four administrative districts of Changsha, China by stratified random sampling. The intelligence characteristics of children with varying degrees of sleep deprivation were investigated using the Chinese Wechsler Intelligence Scale for Children. RESULTS: A total of 286 valid questionnaires were received, with a response rate of 90.5%. The survey was comprised of a sleep deprivation group (sleep time <8 hours per night; n=180) and a control group (sleep time ≥8 hours per night; n=106). The sleep deprivation group had significantly lower subtest scores, verbal intelligence quotient (IQ) (VIQ), performance IQ (PIQ) and full scale IQ (P<0.05) and significantly lower verbal comprehension factor score and memory/attention factor score compared with the control group (P<0.05). Compared with the control group, the moderate sleep deprivation subgroup had significantly decreased VIQ and full scale IQ as well as verbal comprehension factor score and memory/attention factor score (P<0.05), and the severe sleep deprivation subgroup showed decreases in all scores (P<0.05). The sleep deprivation group and moderate and severe sleep deprivation subgroups had significantly higher proportions of children with VIQ-PIQ imbalance than the control group. CONCLUSIONS: Sleep deprivation adversely affects intelligence development, especially VIQ, in primary school students, and the adverse effects of sleep deprivation are mainly seen in students with moderate and severe sleep deprivation.

[Quantified research about the effects of sleep quality on attention in class and acadamic achievements in primary school children].

OBJECTIVE: To study the adverse effects of sleep problems and sleep insufficiency on attention in class and pupils' acadamic achievements. METHODS: A total of 1138 students from four primary schools at ages of 6-12 years were randomly sampled from four districts of Changsha city, Hunan Province June 2009 to April 2010. The inquired items included sleep problems, sleep time, sleep quality, attention in class and academic achievements. Teachers and parents observed the pupils according to the unified requirements for 3 months and then filled out the questionnaires. RESULTS: The total valid inquiry tables were 1091 with the answering rate of 95.87%, including 549 boys and 542 girls. The sleep quality was more poor in children with sleep problems or sleep insufficiency than in children with normal sleep. The sleep quality was reduced and aggravated along with the increasing sleep problems and the reducing sleep time. The attention in class and academic achievements in children with sleep problems or sleep insufficiency were more poor than in children with normal sleep. The sleep quality index was negatively correlated with attention in class and academic achievements. The attention in class was positively correlated with academic achievements. CONCLUSIONS: The decline in sleep quality directly affects the attention in class and reduce the academic achievements in primary school children.