The Inhibition of Cholinesterases by Antagonists of Acetylcholine and Histamine

Todrick, A.

doi:10.1111/j.1476-5381.1954.tb00820.x

Cited by 37 publications

(17 citation statements)

References 34 publications

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“…Promethazine, however, with a two carbon side chain, a branch on the side chain and methyl groups on (1939,1947), Duke & Pickford (1951) and Duke, Pickford & Watt (1950).) This hypothesis is consistent with the suggestion of Feldberg (1950) Todrick (1954) demonstrated, some have anticholinesterase activity. In addition, several phenothiazine derivatives have been shown to inhibit contraction of skeletal muscles after application of acetylcholine (Jindal & Deshpande, 1961) and electrical activity of the cerebral cortex induced by neostigmine and di-isopropylfluorophosphate (White & Westerbeke, 1961).…”

Section: Resultssupporting

confidence: 77%

The Effects of Drugs on the Release of Vasopressin

Dyball

1968

British Journal of Pharmacology and Chemotherapy

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Section: Resultssupporting

confidence: 77%

The Effects of Drugs on the Release of Vasopressin

Dyball

1968

British Journal of Pharmacology and Chemotherapy

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“…and cocaine 80.0 pg/ml. The potencies of hexamethonium and tubocurarine as anticholinesterases measured by the radiometer technique were similar to those obtained by Todrick (1954) pseudocholinesterase. The amount of acetylcholine (3.3 to 33 ng/ml.)…”

Section: Discussionsupporting

confidence: 73%

The Longitudinal Muscle Component of the Peristaltic Reflex in the Guinea‐pig Isolated Ileum

Schneider

1966

British Journal of Pharmacology and Chemotherapy

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“…Gallamine has been reported to possess anticholinesterase activity in high concentrations (Todrick, 1954), and in the atria, gallamine 1 mM reduced the rate of hydrolysis of ACh by 50%. As such anticholinesterase activity would counteract the antimuscarinic action of gallamine at high concentrations it is of interest that responses to CCh are not potentiated by pretreatment of the animals with DFP (Madden & Mitchelson, 1975) indicating that CCh does not mediate its action by releasing endogenous ACh.…”

Section: Discussionmentioning

confidence: 99%

The Inhibitory Effect of Gallamine on Muscarinic Receptors

Clark¹,

Mitchelson²

1976

British J Pharmacology

235

137

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The inhibitory effect of gallamine (1.1 μM‐1.1 mM) on negative inotropic responses to acetylcholine (ACh) or carbachol (CCh) was investigated in isolated electrically stimulated atria of the guinea‐pig. Gallamine caused parallel rightward shifts of the dose‐response curves to the agonists, with no depression of the maximal response. Gallamine (0.11‐1.1 mM) produced a greater degree of antagonism towards CCh than towards ACh. With either agonist, the degree of antagonism produced by gallamine in high concentrations was less than that expected for a competitive antagonist. Similar findings were made when either negative inotropic or chronotropic responses were recorded in spontaneously beating guinea‐pig atria. The inhibitory effect of gallamine against the negative inotropic response to cholinomimetics in electrically stimulated atria was not altered either in the presence of propranolol (17 μM) or in atria obtained from guinea‐pigs pretreated with diisopropylphosphorofluoridate (DFP) (12.5 μmol/kg, in divided doses over 3 days). When ACh was used as the agonist, combination of gallamine with atropine (0.05‐0.4 μM) produced dose‐ratios which were less than expected for combination of two competitive antagonists. The same phenomenon was observed in atria obtained from guinea‐pigs pretreated with DFP. It is suggested that the antagonism produced by gallamine is a type of non‐competitive inhibition, which has been termed ‘metaffinoid antagonism’. An antagonist of this type allosterically alters the affinity of the agonist for its binding site, rather than changing the effectiveness of the agonist‐receptor interaction.

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The Inhibition of Cholinesterases by Antagonists of Acetylcholine and Histamine

Cited by 37 publications

References 34 publications

The Effects of Drugs on the Release of Vasopressin

The Effects of Drugs on the Release of Vasopressin

The Longitudinal Muscle Component of the Peristaltic Reflex in the Guinea‐pig Isolated Ileum

The Inhibitory Effect of Gallamine on Muscarinic Receptors

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