P型カルシウムチャネルは,蜘蛛の毒素オメガ-アガ-IVAによって遮断されています
I M Mintz1, V J Venema, K M Swiderek
1Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115.
Nature
|February 27, 1992
まとめ
新種のスパイダー毒素であるオメガ-アガ-IVAは,ネズミのニューロンのP型カルシウムチャネルを効果的にブロックします. この発見は,脳のカルシウムチャネルを理解し,新しい神経保護薬の開発に役立ちます.
科学分野:
- 神経科学は神経科学である.
- 薬理学 薬理学とは
- バイオケミストリー バイオケミストリー
背景:
- 電圧依存カルシウムチャネルは,神経機能に不可欠であり,シナプス伝達や遺伝子発現などのプロセスを調節します.
- 既存の高親和性阻害剤は,L型およびN型カルシウムチャネルのみを標的にし,他のタイプは特徴づけられていません.
- P型カルシウムチャネルはネズミのプルキンジェニューロンにおいて極めて重要であるが,特定の高親和性ブロッカーは欠けている.
研究 の 目的:
- 電圧依存カルシウムチャネルのための新しい高親和性ブロッカーを特定する.
- 哺乳類の脳のカルシウムチャンネルに対するオメガ-アガ-IVAの抑制効果を特徴づける.
- 神経保護薬剤の設計におけるオメガ-Aga-IVAの可能性を調査する.
主な方法:
- カルシウムチャネル阻害活性に対するクモの毒成分のスクリーニング.
- P型カルシウムチャネル機能を評価するためにラット・プルキンジェ神経の電気生理学的記録.
- ネズミの脳シナプトソームへのカルシウム流入の測定.
主要な成果:
- オメガ-アガ-IVAの識別,フンネルウェブ蜘蛛の毒からのペプチド毒素.
- omega-Aga-IVAは,ネズミの脳シナプトソームにカルシウムの侵入を強力に阻害することを実証しました.
- この毒素は,ネズミのプルキンジェニューロンにおけるP型カルシウムチャネルを特異的に抑制した.
結論:
- オメガ-アガ-IVAは,P型カルシウムチャネルの強力なブロッカーです.
- この毒素は,現在の阻害剤に抵抗する脳のカルシウムチャネルを特徴付けるための新しいツールを提供します.
- omega-Aga-IVAは,新しい神経保護療法薬の開発を促進する可能性があります.
関連する概念動画
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:09GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
01:22Botulism
Botulism is a life-threatening neuroparalytic condition caused by botulinum neurotoxin, which is produced by the bacterium Clostridium botulinum, a Gram-positive, spore-forming, obligate anaerobe.In adults, the toxin enters the body in different ways: in foodborne botulism, the preformed toxin is absorbed in the intestine. In wound botulism, spores grow in injured tissue and release the toxin into the blood. Infant botulism differs mechanistically from adult forms. In infants, botulism commonly...
01:22American Trypanosomiasis
Chagas disease, or American trypanosomiasis, is a vector-borne parasitic infection caused by Trypanosoma cruzi, a flagellated protozoan (kinetoplastid) of the family Trypanosomatidae. The disease is endemic in Latin America, although cases are increasingly reported worldwide due to human migration. Transmission most commonly occurs when feces of infected triatomine bugs contaminate bite wounds or mucosal surfaces; additional routes include congenital, transfusional, transplant-related, and oral...
01:27Esophageal Achalasia
Esophageal achalasia is a chronic neurogenic disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absent or ineffective peristalsis in the distal esophagus. This leads to a functional obstruction without a physical blockage, despite significant disruption of esophageal motility.EtiologyAchalasia is caused by degeneration of the myenteric (Auerbach's) plexus, specifically the loss of inhibitory ganglion cells that produce vasoactive intestinal peptide (VIP)...
01:26Gastritis II: Pathophysiology
The pathophysiology of gastritis begins with the colonization of the stomach lining by Helicobacter pylori (H. pylori). This bacterium spreads mainly via the oral-oral route through saliva or shared utensils, and can also be transmitted in overcrowded or unhygienic environments through contaminated water, despite its brief survival outside the body.ColonizationOnce ingested, H. pylori enters the stomach and begins colonization by navigating through the mucus layer lining the stomach wall. It...