A sensitive radioreceptor assay for atropine in plasma

Metcalfe, Roger F.

doi:10.1016/0006-2952(81)90079-4

Cited by 36 publications

(5 citation statements)

References 4 publications

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“…The most sophisticated methods used in the analysis of atropine and its degradation products are reversedphase high pressure liquid chromatography (1 7), gas chromatographic-mass spectrometric assay ( 18), mass fragmen tography ( 19) and radioreceptor assay (20,21). In these methods atropine levels down to 0.1 to 0.9 ng/ml can be determined with good reproducibility and accuracy.…”

Section: R Q Determinationmentioning

confidence: 99%

Pharmacokinetic implications for the clinical use of atropine, scopolamine and glycopyrrolate

Kanto

Klotz

1988

Acta Anaesthesiol Scand

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Several specific and sensitive new methods for determining atropine and its metabolites in biological fluids have increased the possibility to characterise the pharmacokinetic properties of this antimuscarinic agent. Following i.v. injection, atropine disappears very quickly from the circulation, resembling its fast onset of action. Age, but not sex, appears to have a clear effect on its kinetics, explaining at least partly the higher sensitivity of very young and very old patients to this anticholinergic agent. Following i.m. or oral atropine administration, typical anticholinergic effects coincide quite well with the absorption rate of the drug, indicating that the premedication should be given about 1 and 2 h before induction of anaesthesia. A sufficient absorption after rectal administration offers an alternative treatment, especially in children. Differing from its placental transfer, atropine has a delayed and incomplete lumbar cerebrospinal fluid penetration, indicating a fundamental difference between these two biological membranes. Oropharyngeally administered atropine has a very variable absorption, but inhaled or intratracheally given drug has produced interesting new results, e.g. pulmonary atropine administration appears to have clinical significance in special situations, such as cardiac arrest and organophosphate poisoning (military personnel). Depending on the method used, different data on the metabolism and excretion for atropine have been reported and therefore further studies are needed in this respect. The pharmacokinetics of scopolamine and glycopyrrolate and their relation to clinical response are poorly understood.

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Section: R Q Determinationmentioning

confidence: 99%

Pharmacokinetic implications for the clinical use of atropine, scopolamine and glycopyrrolate

Kanto

Klotz

1988

Acta Anaesthesiol Scand

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“…However, the current data show that plasma and serum inhibits [ 3 H]QNB binding to rat brain membranes by more than 50%, a conclusion that other reports support. As early as 1981, it was reported that 10% plasma (an amount typically used in the SAA assay) inhibits [ 3 H]QNB binding to pig brain muscarinic receptors by 70% 8 . This inhibition was attributed to [ 3 H]QNB's binding to plasma proteins, because when the plasma was filtered on a Centriflo cone (Millipore) with a molecular‐weight cutoff of 50 kDa, the filtered plasma showed no inhibition of [ 3 H]QNB binding to muscarinic receptors 8 …”

mentioning

confidence: 99%

“…As early as 1981, it was reported that 10% plasma (an amount typically used in the SAA assay) inhibits [ 3 H]QNB binding to pig brain muscarinic receptors by 70%. 8 This inhibition was attributed to [ 3 H]QNB's binding to plasma proteins, because when the plasma was filtered on a Centriflo cone (Millipore) with a molecular-weight cutoff of 50 kDa, the filtered plasma showed no inhibition of [ 3 H]QNB binding to muscarinic receptors. 8 In summary, the present study demonstrates that the frequently used serum anticholinergic assay is not an accurate representation of anticholinergic activity because of extensive binding of [ 3 H]QNB to plasma proteins.…”

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confidence: 99%

Flaws in the Serum Anticholinergic Activity Assay: Implications for the Study of Delirium

Cox

Kwatra

Shetty

et al. 2009

J American Geriatrics Society

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“…Plasma was separated from the red cells and frozen immediately at -70°C until assayed. Hyoscine concentrations were determined using a modified method of Metcalfe (1981), Muir & Metcalfe (1983) and Cintron & Chen (1987). Brain tissue was homogenized (100 mgmL-') in perchloric acid (0.1 M), and the homogenates were neutralized with sodium tetraborate (0.1 M).…”

Section: Hyoscine Assaymentioning

confidence: 99%

Continuous Administration of Low Dose Rates of Physostigmine and Hyoscine to Guinea-pigs Prevents the Toxicity and Reduces the Incapacitation Produced by Soman Poisoning

Wetherell

1994

Journal of Pharmacy and Pharmacology

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A regime was developed, using mini-osmotic pumps, for the continuous subcutaneous administration of low doses of physostigmine (12.1, 9.7, 4.85 and 2.43 micrograms h-1), in combination with hyoscine (1.94 or 0.39 micrograms h-1), to guinea-pigs for up to 13 days. Physostigmine, in combination with hyoscine, inhibited plasma cholinesterase, and red blood cell and brain acetylcholinesterase, in a concentration-dependent manner, did not affect the normal growth rate of guinea-pigs, and produced no obvious signs of poisoning. A dose rate of 4.85 micrograms h-1 physostigmine and 1.94 micrograms h-1 hyoscine was required to inhibit red cell acetylcholinesterase by 30% and brain acetylcholinesterase by 5-15%, with an accompanying plasma hyoscine concentration of 700-850 pg mL-1. There was an apparent decline in red cell acetylcholinesterase activity during the 13 days. Hyoscine levels were higher in the cholinergic-rich areas of the brain than in the plasma. Continuous pretreatment (1 or 6 days) with physostigmine (4.84 micrograms h-1) and hyoscine (1.94 micrograms h-1) provided complete protection against the lethal effects, and minimized the incapacitation and weight loss produced by soman at a dose equivalent to the LD99 value. Following soman challenge, guinea-pigs exhibited early signs of soman poisoning, but generally these signs of poisoning were minimal by 1-2 h. Extending the pretreatment time to 13 days protected 75% of the guinea-pigs against the lethal effects of soman poisoning. Red cell acetylcholinesterase activity, 24 h after soman poisoning, was higher following continuous pretreatment with physostigmine and hyoscine than after acute treatment with atropine.

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A sensitive radioreceptor assay for atropine in plasma

Cited by 36 publications

References 4 publications

Pharmacokinetic implications for the clinical use of atropine, scopolamine and glycopyrrolate

Pharmacokinetic implications for the clinical use of atropine, scopolamine and glycopyrrolate

Flaws in the Serum Anticholinergic Activity Assay: Implications for the Study of Delirium

Continuous Administration of Low Dose Rates of Physostigmine and Hyoscine to Guinea-pigs Prevents the Toxicity and Reduces the Incapacitation Produced by Soman Poisoning

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