Inhibition of acetylcholine synthesis by juglone and 4-(1-naphthylvinyl) pyridine
| Autor: | Paulina F.L. Wang, Dean R. Haubrich |
|---|---|
| Rok vydání: | 1976 |
| Předmět: |
Male
Pyridines Endogeny In Vitro Techniques Pharmacology Biochemistry Choline Choline O-Acetyltransferase Mice chemistry.chemical_compound Acetyltransferases In vivo Pyridine medicine Animals chemistry.chemical_classification Brain Choline acetyltransferase Acetylcholine Kinetics Enzyme chemistry Rabbits Naphthylvinylpyridine Juglone Naphthoquinones medicine.drug |
| Zdroj: | Biochemical Pharmacology. 25:669-672 |
| ISSN: | 0006-2952 |
| DOI: | 10.1016/0006-2952(76)90242-2 |
| Popis: | Inhibition by juglone (5-hydroxy-l,4-naphthoquinone) of choline acetyltransferase [ChAt; acetyl-CoA: choline O-acetyltransferase (EC 2.3.1.6)] of rabbit brain was noncompetitive for choline and not reversible by dialysis. When acetyl-CoA and juglone were mixed together before the addition of ChAt, inhibition was competitive with respect to acetyl-CoA: when juglone was preincubated with the enzyme, inhibition was mixed competitive and noncompetitive. The effects in vivo of juglone and 4-(l-naphthylvinyl) pyridine (NVP) were determined in brains of mice sacrificed by microwave radiation. Changes in the rate of synthesis of acetylcholine were assessed by measuring the amount of choline-methyl[3H] converted to acetylcholine in the brains of mice 30 sec after the intravenous administration of the isotope. Administration of two doses of juglone (2 mg/kg. 1 hr apart) increased the concentrations of both endogenous and radioactive choline in brain, but had no effect on either the rate of synthesis or the concentration of acetylcholine. These results suggest that juglone, when administered to animals, does not inhibit brain ChAt. On the other hand, administration of two doses of 4-(1-naphthylvinyl) pyridine (100 mg/kg, i.p., 1 hr apart) did inhibit the synthesis of acetylcholine, but had no effect on the concentration of either choline or acetylcholine in brain. This latter finding indicates that inhibition of ChAt can occur in vivo without causing a reduction in the concentration of acetylcholine. |
| Databáze: | OpenAIRE |
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