ピクロトキシン

解説C30H34O13 。コッカリンともいう。インド，ピクロトキシニンpicrotoxininとピクロチンpicrotin(これ自身に毒性はない)の各1分子からなる分子化合物。ツヅラフジ科のつる性の低木アナミルタ Anamirta cocculusの種子に含まれる苦みのある有毒成分。中枢神経興奮作用があり，アルコールから光沢のある長斜方形の葉状結晶となる。水溶性。医薬としても用いられ，中枢興奮剤やバルビツル酸の解毒に利用される。副作用は，急性のけいれんや錯乱。ピクロトキシンによる痙攣は間代性痙攣で，作用部位は中枢神経全域にわたるが，とくに脳幹に強く作用する。ブリタニカ国際大百科事典 小項目事典 ブリタニカ

用途ピクロトキシニンとピクロチ ンのそれぞれ1分子より成る分子化合物で す。ピクロトキシン結合部位に作用し、シナ プス前抑制を抑制します。

用途ピクロトキシニンとピクロチ ンのそれぞれ1 分子より成る分子化合物で す。ピクロトキシン結合部位に作用し、シナ プス前抑制を抑制します。

説明Picrotoxin, also known as cocculin, appears as white to light beige crystalline material. It is isolated from Cocculus indicus (Fructus cocculi), fishberries, or Indian berries. Picrotoxin is a colourless, flexible, shining, prismatic crystals, or a micro-crystalline powder. It is odourless, has a very bitter taste, and is permanent in the air. Picrotoxin is soluble in hot water, readily soluble in strong ammonia water, and in aqueous solutions of sodium hydroxide, soluble in dilute acids, and alkalis as well as in glacial acetic acid, sparingly soluble in chloroform and very slightly soluble in cold water and alcohol. Picrotoxin is stable under normal temperatures and pressures and decompose when exposed to light. Picrotoxin is incompatible with strong oxidising agents, strong acids, strong bases, light.

来歴The seeds of Menispermaceae are traditionally used as fishing bait or pesticide, as well as pediculicide . Once it was used for brewing beer to impart a more intoxicating quality to beer in the nineteenth century . In 1812, cocculin was firstly isolated by Pierre Boullay and named picrotoxin, a combination of the Greek words “picros” and “toxicon.” Picrotoxin showed strong physiological action and was once extensively studied.The action mechanism of picrotoxin is a controversial issue. Newland etal. considered that picrotoxin enhanced the occurrence of a desensitized state or an allosterically blocked state of GABAA receptor , while Jong etal. showed that picrotoxinacts as a noncompetitive channel blocker for the GABAA receptor chloride channels, rather than a receptor antagonist .

使用Picrotoxin has been used:as non-competitive antagonist for the γ-aminobutyric acid (GABAA) for studying synchronized burst (SB) dynamicsas a component of extracellular saline for blocking glutamate and acetylcholine receptors in neuronsas a component of artificial cerebrospinal fluid (ACSF) for voltage-clamp recordings studies in dissociated cortical neurons

A poisonous berry, the dried fruit of Anamirta PICROTOXIN L. Contains several substances including about one percent picrotoxin. Pure picrotoxin occurs as shiny leaflets with an intensely bitter taste or as a microcrystalline powder. Very poisonous!. Used in medicine as a central nervous system stimulant and antidote for barbiturate poisoning. Not currently regarded as a useful therapeutic agent.