Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence is presented of the existence of a substance in brain (substance B) that reverses presynaptic inhibition of evoked acetylcholine (AcCho) release. Addition of guinea pig brain synaptosomal incubation medium or whole brain extracts to assays in which 1,1-dimethyl-4-phenylpiperazinium-evoked release of [3H]AcCho from guinea pig myenteric plexus synaptosomes reversed purinergic, muscarinic, and alpha 2-adrenergic agonist inhibition. However, the extracts did not increase basal or evoked release of AcCho. Results of chromatography on Bio-Gel P-2 of a concentrated whole brain extract suggest this factor has an Mr of 700. Substance B was resistant to boiling under acid or alkaline conditions as well as incubation with phospholipase C and various proteases; ashing, however, completely destroyed activity. This endogenous factor was also found to antagonize agonist-mediated inhibition of electrically evoked contractions of myenteric plexus-longitudinal muscle strips from the guinea pig ileum. The demonstration of substance B with its ability to reverse presynaptic inhibition of AcCho release reveals one mode of presynaptic modulation.
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PMID:Substance B: an endogenous brain factor that reverses presynaptic inhibition of acetylcholine release. 287 31

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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PMID:Isolation of a factor that reverses presynaptic inhibition of acetylcholine release. 357 23