Research Progress of GABA Receptors in Alzheimer’s Disease / 中国生物化学与分子生物学报

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with the early symptom of A β plaque, tau hyperphosphorylation neuronal tangle formation in cells. At present, accumulated evidence shows that the changes of GABA receptors are closely related to AD. Some studies have shown that the expression level of each subunit of the GABA receptor changes in AD patients. Therefore, it is speculated that the changes of GABA subunits may be related to the pathogenesis of AD, but there is no better methods to improve AD by targeting GABA receptors. In order to further understand the relationship between the changes of GABA receptors and AD, this paper first reviewed the changes of GABA receptors in AD patients and animal models’ brains and found that there was differential expression in GABA(A) receptor subunits in AD patients. Then we summarized the changes of GABA receptor subunits in Alzheimer database. Based on the data, we found that a few GABA subunits had significant changes. The evidence shows that the change of GABA receptors alters the neural activity in the brain. Other studies have found that the treatment of mice with GABA receptor agonists and antagonists can improve the cognitive ability of mice. We hope that understanding the differential expression of GABA receptors in AD will provide a more accurate target for the treatment of AD.

Pathway analysis of glutamate-mediated, calcium-related signaling in glioma progression.

Brain tumors, particularly high-grade glioblastomas, are a crucial public health issue due to poor prognosis and an extremely low survival rate. The glioblastoma multiforme (GBM) grows rapidly within its unique microenvironment that is characterized by active neural communications. Therefore, diverse neurotransmitters not only maintain normal brain functions but also influence glioma progression. To fully appreciate the relationship between neurotransmitters and glioma progression, we reviewed potential neurotransmitter contributors in human GBM and the much less aggressive Low-grade glioma (LGG) by combining previously published data from gene-mutation/mRNA sequencing databases together with protein-protein interaction (PPI) network analysis results. The summarized results indicate that glutamatergic and calcium signaling may provide positive feedback to promote glioma formation through 1) metabolic reprogramming and genetic switching to accelerate glioma duplication and progression; 2) upregulation of cytoskeleton proteins and elevation of intracellular Ca2+ levels to increase glutamate release and facilitate formation of synaptic-like connections with surrounding cells in their microenvironment. The upregulated glutamatergic neuronal activities in turn stimulate glioma growth and signaling. Importantly, the enhanced electrical and molecular signals from both neurons and glia propagate out to enable glioma symptoms such as epilepsy and migraine. The elevated intracellular Ca2+ also activates nitric oxide synthase to produce nitric oxide (NO) that can either promote or inhibit tumorigenesis. By analyzing the network effects for complex interaction among neurotransmitters such as glutamate, Ca2+ and NO in brain tumor progression, especially GBM, we identified the glutamatergic signaling as the potential therapeutic targets and suggest manipulation of glutamatergic signaling may be an effective treatment strategy for this aggressive brain cancer.

Synthesis and insecticidal activity studies of novel phenylpyrazole derivatives containing arylimine or carbimidate moiety.

Phenylpyrazole insecticides are successful for crop protection and public hygiene by blocking gamma-aminobutyric acid (GABA)-gated chloride channels and glutamate-gated chloride (GluCl) channels. A series of novel phenylpyrazoles containing arylimine or 1-methoxyaryl groups were designed and synthesized. The addition reaction of methanol to the imines 1-11 was investigated and the cayno addition products 13-15 were obtained. The compounds 1-15 were confirmed by 1H NMR and elemental analysis. The results of bioassay indicated that some compounds exhibited comparable bioactivity to fipronil against a broad spectrum of insects such as bean aphid (Aphis craccivora), mosquito (Culex pipiens pallens), diamondback moth (Plutella xylostella) and Oriental armyworm (Mythimna separata). Especially, the foliar contact activity against bean aphid of compound 7 at 10 µg mL-1 was 68%, the larvacidal activity against mosquito of compounds 5, 13 and 15 at 0.0025 µg mL-1 was 100%, the larvacidal activity against diamondback moth of compounds 9 and 11 at 0.05 µg mL-1 was 100%, the larvacidal activity against Oriental armyworm of compound 9 at 1 µg mL-1 was 100%. The 3-cayno moiety on pyrazole ring was essential for the high insecticidal activities against bean aphid, diamondback moth and Oriental armyworm, while the 3-carbimidate moiety on pyrazole ring was crucial to the excellent high insecticidal activities against mosquito.

Romaine Lettuce/Skullcap Mixture Improves Sleep Behavior in Vertebrate Models.

The aim of this study is to investigate the effects of romaine lettuce leaves extract (RE), skullcap root extract (SE) and their mixture on sleep behaviors in vertebrate models. HPLC analysis showed that RE contains lactucopicrin (0.02±0.01 mg/g extract), chlorogenic acid (4.05±0.03 mg/g extract), caffeic acid (2.38±0.03 mg/g extract), and chicoric acid (7.02±0.32 mg/g extract) as main phenolic compounds, while SE includes baicalin (99.4±0.5 mg/g extract), baicalein (8.28±0.21 mg/g extract), and wogonin (3.09±0.32 mg/g extract). The mixture of RE (100 mg/g extract) and SE (40 mg/g extract) increased total sleep time by 50.9% compared with the control in pentobarbital-induced sleep model. In electroencephalography (EEG) analysis, RE/SE mixture significantly increased Non-Rapid Eye Movement (NREM), in which delta wave was enhanced by around 40% compared with normal control, leading to the increase of sleep time. In caffeine-induced wake model, RE/SE mixture greatly decreased (53%) caffeine-induced wake time, showing a similar level to normal control. In addition, caffeine-induced decreased of NREM and delta wave effectively increased with RE/SE mixture; NREM and delta wave increased by 85% and 108%, respectively. Furthermore, RE/SE mixture was shown to bind to a gamma-aminobutyric acid type A (GABAA)-benzodiazepine (BZD) receptor stronger than RE or SE single extract. Taken together, RE/SE mixture effectively improved sleep behavior with the increase of NREM via GABAA-BZD receptor binding. RE/SE mixture can be used as an herbal agent for sleep disorders.

Pharmacologic Considerations during the Preoperative Evaluation of Neurologic Patients.

BACKGROUND: Optimizing a patient for surgery is a central goal during the preoperative period. Patients with common neurologic disorders, such as Alzheimer's disease, epilepsy, Parkinson's disease, and multiple sclerosis may require special attention in the perioperative management of their neurologic medications. OBJECTIVE: This review aims to organize the most current recommendations for neurologic medication management during the perioperative period to minimize the risk of postoperative neurologic decline. METHODS: A review of current literature present on PubMed and Medline of peer-reviewed research papers was conducted. The quality of the papers was assessed according to their research methodology and many of their sources were further analyzed in the same manner. A focused review question for each disease type was used, and, at times, inclusion and exclusion criteria were applied. RESULTS: Manuscripts covered a wide range of medical subspecialties with the most common sources being anesthetic, neurologic, and pharmacologic journals. CONCLUSION: The systemic inflammation that occurs in the perioperative period is detrimental to a patient's neurologic status. It is important to recognize that the proper management of neurologic medications can limit the negative effects of these stresses on a patient. Most medications appear safe to continue until the morning of surgery. Consultation with a neurologist regarding continuation of specific medications may be necessary to further ensure patient safety.

Whole-exome sequencing in an individual with severe global developmental delay and intractable epilepsy identifies a novel, de novo GRIN2A mutation.

We present a 4-year-old girl with profound global developmental delay and refractory epilepsy characterized by multiple seizure types (partial complex with secondary generalization, tonic, myoclonic, and atypical absence). Her seizure semiology did not fit within a specific epileptic syndrome. Despite a broad metabolic and genetic workup, a diagnosis was not forthcoming. Whole-exome sequencing with a trio analysis (affected child compared to unaffected parents) was performed and identified a novel de novo missense mutation in GRIN2A, c.2449A>G, p.Met817Val, as the likely cause of the refractory epilepsy and global developmental delay. GRIN2A encodes a subunit of N-methyl-d-aspartate (NMDA) receptor that mediates excitatory transmission in the central nervous system. A significant reduction in the frequency and the duration of her seizures was observed after the addition of topiramate over a 10-month period. Further prospective studies in additional patients with mutations in GRIN2A will be required to optimize seizure management for this rare disorder. This report expands the current phenotype associated with GRIN2A mutations.