Isolation of a factor that reverses presynaptic inhibition of acetylcholine release
Abstract:
A factor (Substance B) has been isolated from brain which reverses the presynaptically-modulated inhibition of evoked ACh release from both guinea-pig myenteric plexus-longitudinal muscle synaptosomes and the intact strip. Inhibitory modulating agents whose activity is reversed by Substance B include oxotremorine, 2-chloroadenosine, clonidine, and morphine. In addition to brain, Substance B is also present in heart and ileum but not in liver or kidney. As determined by Biogel P2 chromatography, this factor appears to have a molecular weight of around 700. It is not destroyed by preincubation with periodate, amylase, adenosine deaminase, pronase, trypsin, phospholipase C or carboxypeptidase Y.
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