癫的微创外科治疗

近年来发展起来的癫癎外科方法已成为顽固性癫癎治疗的重要手段,其中开颅手术创伤较大,而微创方法治疗癫癎仍处于探索之中.本文就目前临床应用较广的脑神经刺激术、立体定向放射治疗、大脑刺激术和立体定向毁损等四种微创外科治疗方法进行综述.     

儿童癫性精神障碍51例临床分析

目的了解儿童癫     

内侧颞叶癫病人脑组织GABRG2基因变异研究

目的探讨GABRG2基因变异与内侧颢叶癫癎的关系.方法运用RT-PCR方法测定内侧颞叶癫癎致癎灶和其他类型癫癎病人手术切除脑组织内的GABRG2基因mRNA序列.结果全组共发现3处单核苷酸多态性,其电内侧颞叶癫癎组245 G→A出现频率与对照组存在统计学差异.结论GABRG2基因突变极有可能在内侧颞叶癫癎的发病中起重要作用.     

Effects of -arginine on the afferent resting activity in the cephalopod statocyst

The effects of bath application of the nitric oxide (NO) precursor -arginine ( -ARG) on the resting activity (RA) of afferent crista fibers were studied in isolated statocysts of the cuttlefish Sepia officinalis under various experimental conditions. -ARG (threshold 10⁻⁷ M) had three different effects: inhibition, excitation, and excitation followed by an inhibition; only the inhibitory effect of -ARG was dose-dependent. -Arginine ( -ARG) had no effect. When the preparation was pre-treated with NO synthase inhibitors (N^G-Nitric- -arginine methyl ester HCl ( -NAME), N^G-Nitro- -arginine ( -NOARG)), both the inhibitory and the excitatory effects of -ARG significantly decreased at higher concentrations (10^{−5 to −4} M), or were completely blocked at lower concentrations (10^{−7 to −6} M), of -ARG. When the preparation was pre-treated with guanylate cyclase inhibitors (1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ), methylene blue (M-BLU), cystamine (CYS)), -ARG had only excitatory effects, whereas its effects were only inhibitory when the preparation was pre-treated with adenylate cyclase inhibitors 2′,3′-dideoxyadenosine (DDA), MDL-12330A (MDL), nicotinic acid (NIC-A)). -ARG had no effects when the pre-treatment was with a guanylate cyclase inhibitor and an adenylate cyclase inhibitor combined; in that situation, the RA of the afferent fibers remained. These data indicate that in cephalopod statocysts, a cGMP and a cAMP signal transduction pathway (presumably via the generation of NO) are responsible for the effects of -ARG on the RA of crista afferent fibers. They also indicate that the -ARG–cGMP pathway is the dominant pathway and is inhibitory, and that both pathways have only modulatory effects on, but are not essential for, the generation of the RA.     

Intracellular ATP depletion inhibits swelling-induced -[H]aspartate release from primary astrocyte cultures

Volume expansion-sensing outward rectifier (VSOR) anion channel, also referred to as volume-sensitive organic osmolyte-anion channel (VSOAC), appears to be responsible for cell swelling-induced amino acid release in a variety of cells. One prominent feature of the VSOR/VSOAC is that non-hydrolyzed intracellular ATP binding to the channel or an accessory protein is required for its activation. In this study, the effect of intracellular ATP depletion on the swelling-induced release of -[³H]aspartate from rat primary astrocyte cultures due to exposure to either high K⁺ or hypotonic media was studied. When the cells were pretreated for 10 min with a combination of the metabolic inhibitors 2-deoxyglucose and rotenone, 100 mM K⁺ media- or hypotonic media-induced -[³H]aspartate release was completely suppressed. Added separately, each inhibitor showed only partial or no inhibition of -[³H]aspartate release, which correlated with its relative effectiveness in decreasing intracellular ATP levels. These data are consistent with the view that during high [K⁺]_o or hypotonic media-induced swelling of primary astrocyte cultures an ATP-dependent swelling-activated VSOAC channel is responsible for -[³H]aspartate release and close to normal ATP is required for full channel activation.     

Low-threshold N-methyl- -aspartate receptor function correlates negatively with learning

The intermediate, medial hyperstriatum ventrale (IMHV) is an area of the forebrain of the domestic chick which exhibits great plasticity. Moreover, there is a strong link between plasticity in the IMHV and specific changes in behaviour. The IMHV in vitro is still plastic, and many of its physiological properties are age-dependent, peaking in slices taken from 3- or 4-day-old birds. This 'window' coincides with an important transitional period in a chick's normal behavioural development. It has also been claimed that reversal training is at its most effective in 3- and 4-day-old birds - a proposition which was confirmed by the experiments reported here. A combination of in vivo training followed by in vitro electrophysiology also revealed that the function of low-threshold N-methyl-D-aspartate receptors (one of the age-related variables) is negatively related to the effectiveness of reversal training, when age is held constant.     

Pharmacokinetics and pharmacodynamics of -arginine in rats: a model of stimulated neuronal nitric oxide synthesis

Nitric oxide (NO) is believed to be involved in a variety of central nervous system (CNS) functions, including opioid responsivity. Elucidation of the role of NO in the CNS requires the ability to elevate systematically neuronal NO concentrations in vivo. This study was conducted to assess the pharmacokinetics of -arginine, a NO precursor, and to relate the disposition of this amino acid to the pharmacodynamic endpoint of neuronal NO production. -Arginine (250-, 500-, or 1000-mg/kg/h) or saline was infused intravenously for 6 h to rats. -Arginine was quantified in brain and blood (after in vivo microdialysis) with high-performance liquid chromatography. NO was quantified simultaneously with a sensitive and specific amperometric sensor placed in the hippocampus. The data were fit with a comprehensive pharmacokinetic–pharmacodynamic (PK/PD) model to obtain parameters governing the systemic disposition of -arginine, the uptake of -arginine into the brain, and subsequent NO production. Exogenous administration of -arginine resulted in incremental elevations in hippocampal NO, with a 33, 48, and 50% increase from control for the 250-, 500-, and 1000-mg/kg/h -arginine treated rats, respectively. The PK/PD model, which incorporated known characteristics of the system (saturable uptake of -arginine into brain; NO production governed by circadian changes in enzyme activity) was capable of describing accurately the observed data. The model developed herein will be invaluable in characterizing the numerous roles of NO in the CNS.     

Electromyographic Activity Patterns of Ankle Flexor and Extensor Muscles during Spontaneous and -DOPA-Induced Locomotion in Freely Moving Neonatal Rats

In rats, hindlimb postural and locomotor functions mature during the first 3 postnatal weeks. Previous evidence indicates that maturation of descending monoaminergic pathways is important for the postnatal emergence of locomotion with adequate antigravity postural support. Here we have studied the effect of the monoamine precursor -DOPA on locomotor activity in freely moving postnatal rats (7–9 days old) using electromyographic recordings from ankle extensor (soleus) and flexor (tibialis anterior or extensor digitorum longus) muscles. Before pharmacological treatment, both muscles were usually silent at rest, and during spontaneous movements there was a high degree of coactivation between the two antagonists. This was due to a longer electromyographic (EMG) burst duration in flexors, which partly overlapped with the extensor burst. -DOPA administration (150 mg/kg) resulted in a marked increase in postural tonic EMG activity in extensors which appeared gradually within 10 min after injection and was sufficient for the pups to maintain a standing posture with the pelvis raised above ground. Thereafter, episodes of locomotion characterized by rhythmic reciprocal bursts of EMG activity in flexor and extensor muscles were seen. The -DOPA-induced rhythmic EMG pattern was also seen in postnatal rats subjected to a midthoracic spinal cord transection, indicating that the effect of -DOPA on motor coordination is exerted primarily at the level of the spinal pattern generator. Analysis of EMG burst characteristics showed that the pattern of -DOPA-induced locomotion in both intact and spinalized postnatal rats resembled in some respects that observed in adults during spontaneous locomotion. The appearance of reciprocal activation during - DOPA-induced locomotion in neonates was primarily due to a shortening of the EMG burst duration in flexors, which reduced the degree of antagonist coactivation. These results show that the spinal cord has the potential to produce coordinated overground locomotion several days before such movements are normally expressed in the freely moving animal.