Improved Automatic Apparatus for Pharmacological Assays on Isolated Preparations

Boura, A. L. A.; Mongar, J. L.; Schild, H. O.

doi:10.1111/j.1476-5381.1954.tb00811.x

Cited by 56 publications

(45 citation statements)

References 6 publications

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“…The peritoneal washings from at least five rats were pooled and kept on ice until used. The washings were centrifuged at 250 g for 6 min, the supernatant was discarded and the cell pellet resuspended in cold Tyrode (3 ml per rat) of the following composition (mM): NaCl 137; NaHCO3 12; NaH2PO4 0.3; KCI 2.7; MgCl2 1.0; dextrose 5.6 Released and residual histamine were assayed on the atropinized guinea-pig ileum (Boura, Mongar & Schild, 1954) and the released histamine was expressed as % total and corrected for spontaneous release in Tyrode alone (normally about 2%). The total histamine content ranged between 2-6 ,g per 0.5 ml aliquot of cells.…”

Section: Methodsmentioning

confidence: 99%

Inhibition by Cromoglycate of Histamine Release From Rat Peritoneal Mast Cells Induced by Mixtures of Dextran, Phosphatidyl Serine and Calcium Ions

Garland¹,

Mongar²

1974

British J Pharmacology

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1Dextran releases histamine from rat peritoneal mast cells in the presence but not in the absence of phosphatidyl serine (PS). With PS (10 ,g/ml) present the effect of dextran was concentration-dependent in the range of 0.2-6 mg/ml. 2 PS releases little histamine on its own but mixed with dextran (6 mg/ml) produces a graded effect in the range of 0.3-10 Mg/ml.3 The combination of dextran and PS releases no histamine in a medium containing less than 0.1 mm calcium. As the calcium concentration is increased, release occurs and a maximum is reached at calcium 1 mM; at higher concentrations release falls off sharply.4 Histamine release by the combination of dextran (6 mg/ml), PS (10 mg/ml) and calcium (1.8 mM) is inhibited by cromoglycate in the same range (1-30 gM) that inhibits anaphylactic histamine release from rat peritoneal cells. 5 Inhibition by cromoglycate occurred with all dextran concentrations tested (0.2-15 mg/ml) but high concentrations of PS (30 and 100 Mg/ml) overcame the effect of cromoglycate (2 and 10 uM). Calcium concentrations above 1 mM augmented inhibition by cromoglycate 2 and 10 AM.

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Section: Methodsmentioning

confidence: 99%

Inhibition by Cromoglycate of Histamine Release From Rat Peritoneal Mast Cells Induced by Mixtures of Dextran, Phosphatidyl Serine and Calcium Ions

Garland¹,

Mongar²

1974

British J Pharmacology

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“…The 'tissue was suspended in an oxygenated Tyrode solution which was contained in the 2.0 ml. bath of an automatic assay apparatus of the type described by Boura, Mongar, and Schild (1954). Doses of ACh bromide (usually 0.0125 pg.…”

Section: Methodsmentioning

confidence: 99%

The Mode of Action of Some Non‐specific Acetylcholine Antagonists

Timms

1956

British Journal of Pharmacology and Chemotherapy

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Antihistamines such as 2(N-benzyl-N-phenylaminomethyl)-iminazoline hydrochloride (antazoline hydrochloride) and N-dimethyl-aminoethyl benzhydryl ether hydrochloride (diphenhydramine hydrochloride), have been shown to possess many sideeffects (Dutta, 1949), including local anaesthetic effects, antagonism of the depressant action of acetylcholine on the heart, depression of the maximal rate at which the isolated rabbit auricles will respond to electrical stimulation, antagonism of acetylcholine on isolated frog rectus abdominis muscle, and depression of the contraction of the nictitating membrane in response to preganglionic stimulation. Often, the concentrations of antihistamines required to produce such effects considerably exceed those necessary to produce the more specific effects against histamine, so that their modes of action are obscure. Marshall (1955a) claimed to have shown that the antagonism between many antihistamines and histamine on the guineapig ileum is competitive, although the criteria upon which competition was judged are not in entire agreement with those adopted in this paper.A report is presented upon a preliminary investigation into the mode of action of two series of antihistamines as antagonists of acetylcholine (ACh) on the isolated guinea-pig ileum. METHODSThe structure of the two series of compounds used in this work appear in Tables I and II. The lever used throughout this work was constructed according to the dimensions suggested by Schild (1947), and was not allowed to move more than 30°from the horizontal. These precautions ensure that all measurements of the heights of excursions from the kymograph paper are linearly related to the actual shortening of the muszle.Measurement of Anti-Acetylcholine Activity.-In order to determine the anti-ACh activity of these compounds, pA2 andpA10 values (Schild, 1947) were measured against ACh on the isolated guinea-pig ileum. The 'tissue was suspended in an oxygenated Tyrode solution which was contained in the 2.0 ml. bath of an automatic assay apparatus of the type described by Boura, Mongar, and Schild (1954). Doses of ACh bromide (usually 0.0125 pg. base/ml. as basic dose) were added every 2 min. and antagonists were allowed to remain in contact for 10 min., represented by 5 complete cycles of the apparatus. pA2 and pALO values for each compound were not always determined on the same sample of ileum. Samples of ileum which did not recover fully from the effects of the antagonists were discarded, and fresh samples were used for the next test (Schild, 1947). Four determinations of pA2 and four of pA10 were carried out for each substance using samples of intestine from different guinea-pigs.Concentration-action Curves.-In order to determine the validity of the pA method as applied to the activedrug/antagonist systems studied, concentration-action curves were plotted for the active substance, ACh or histamine, first alone and then after equilibration to a fixed concentration of antagonist (Schild, 1949). The importance of such curves is discusse...

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“…In addition to the uniselector controlling the cycle of operations a second uniselector could be used to perform an assay; 4 different agonist solutions being used in varying order to produce the contractions: up to 48 contractions could be used in the assay (12 groups of 4 arranged in 3 Latin squares). A similar arrangement has been used by Boura, Mongar, and Schild (1954). RESULTS…”

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confidence: 99%