マイアネシンの末梢作用に關する新知見—特に線維束性攣縮の問題に關聯して

On the Peripheral Action of Myanesin:Particulary in Relation to Fasciculation

　輓近神經疾患に對する各種の藥劑が相次いで現われ，單に治療効果のみならず神經系の各部位に對する藥劑の選擇作用を利用することによつて神經系の生理及病理の究明に寄與しつつある。著者等も臨床生理及藥理學的見地から此の方面め研究に多大の期待を抱いているものであり本小論文もかかる意圖に基く研究の一部である。

　著者等は先に種々なる中樞神經疾患に對する「マ」の効果について報告したが，特にその際「マ」が線維束性攣縮をも減弱乃至消失せしめうる事實について注目した^1）。この事は從來知られている「マ」の作用機序からでは説明がつかず，方々線維束性攣縮の發現機轉も未解決であるので，實驗的に線維束性攣縮に對する「マ」の作用を追求して，從來殆んど知られていない「マ」の末梢作用につき多少の新知見を得，且つ線維束性攣縮の發現機轉についても若干の考察を加え得るに至つたのでここに報告する。

Since Berger and Bradley described the eff-ects of myanesin in 1946, numerous publication have appeared, dealing with this agent. But none had paid attention to its effects on mu-scular fasciculations. The authors experienced in various diseases, such as syringomyelia, amyotrophic lateral sclerosis and myelitis that the fasciculations as well as other symptoms were vulnerable to myanesin. Also in rabbit the generalized fasciculations of skeletal mu-scles, produced by intraperitoneal injection of vagostigm.ine (a derivate of physostigmine), were inhibited completely by this agent.

It is known that myanesin acts on internun-cial cells. The authors also observed the in-hibiting action of myanesin on the exaggerated multineuron-arc reflex in experimental tetanus.

About the peripheral action of this agent there is nothing but Berger's rpeorts that it has curare like as well as procain like action in excessive dosis. The following result was obtained in our experiment in toads, in which the effect of myanesin on the threshold of stimuli for nerve-muscle preparations and for the endplateless parts of sartorius were stu-died : in excessive dosis it had a direct effect on muscle fibers themselves, but in the con-centration of approximately 15mg per cent it hae no effect on muscles and blocked only the nerve.

Fasciculations induced by vagostigmine are known to yield antidromic impulses and from this fact Forster and his co-workers state, "It is conceivable that such impulses could exert a synchronizing effect on the muscle fibrils by means of an axon reflex." In accordance with this assumption, the authors came to the con-clusion that the inhibiting effect of myanesin on fasciculations is due to the inhibition of axon reflexes by blocking of the nerves.