Disease relevance of hyoscyamine

• This might at least partly explain the advantage of combining 1-hyoscyamine and an oxime with diazepam in intoxications with anticholinesterases [1].

High impact information on hyoscyamine

• Serum concentrations of l-atropine reached 80 to 160 nM within 6 hr, whereas densities of binding sites for [3H]QNB did not show a significant increase until after the second day of infusion and receptor densities did not reach new steady state levels until after the fourth day of infusion [2].
• Chronic administration of l-atropine to rats caused a dose-dependent increase (30%) in the density of muscarinic receptors, as measured with [3H]quinuclidinyl benzilate ([3H]QNB], in cortex (CTX), dorsal hippocampus (DH), and heart but not the corpus striatum [2].
• Determination of L-hyoscyamine in atropine and D-hyoscyamine in L-hyoscyamine by chiral capillary electrophoresis as an alternative to polarimetry [3].
• A prospective, double-blind trial of L-hyoscyamine versus glucagon for the inhibition of small intestinal motility during ERCP [4].
• The enzyme has an average Mr of 41,000 as determined by gel filtration on Superose 12 and exhibited maximum activity at pH 7.8 l-Hyoscyamine and 2-oxoglutarate are required for the enzyme activity, with respective Km values of 35 microM and 43 microM [5].

Biological context of hyoscyamine

• The effect of pirenzepine and L-hyoscyamine on gastric emptying and salivary secretion in healthy volunteers [6].
• The salivation was significantly more inhibited by L-hyoscyamine than by pirenzepine [6].
• In contrast the clinical effects of 1-hyoscyamine seem to be independent of food intake [7].
• Large interindividual differences characterized the absorption and elimination phases of 1-hyoscyamine kinetics [8].
• The plasma concentrations of l-hyoscyamine and the change in heart rate expressed as percentages showed a linear correlation: concentrations under 0.5 micrograms/l caused slowing of rate, higher concentrations caused acceleration [9].

Anatomical context of hyoscyamine

• Pirenzepine in doses inhibiting gastric acid secretion does not delay gastric emptying when compared with an equipotent dose of a classical anticholinergic drug, nor does it inhibit salivary secretion as much as L-hyoscyamine [6].
• Phenthonium (10-50 microM), a quaternary derivative of 1-hyoscyamine, increases the frequency of miniature end-plate potentials (2-5 fold) and blocks the nicotinic receptor-ionic channel in skeletal muscles [10].
• Prejunctional effect of quaternary derivatives of l-hyoscyamine at the rat neuromuscular junction. A structure-activity relationship study [11].

Associations of hyoscyamine with other chemical compounds

• A method for the separation of atropine enantiomers, D- and L-hyoscyamine by capillary electrophoresis (CE) has been developed and validated [3].
• Influence of food on the effect of propantheline and L-hyoscyamine on salivation [7].
• Submaximal doses of atropine or l-hyoscyamine delayed and slowed SVD; higher doses blocked completely. d-Hyoscyamine did not change SVD or acetylcholine vasodilation, but when administered prior to l-hyoscyamine, threshold for blockade of SVD by the l-isomer increased 10,000-fold [12].
• Atropine and l-hyoscyamine are recognized equally well by the antibodies, but some other structurally related drugs (homatropine scopolamine) and atropine hydrolysis products (tropine, tropic acid) do not interfere [13].

Gene context of hyoscyamine

• A method using L-hyoscyamine for the study of muscarinic acetylcholine receptor binding in vivo [14].

Analytical, diagnostic and therapeutic context of hyoscyamine

• Good correlation between HPLC and HPTLC quantitative results was measured (correlation coefficients of mean values were 0.92086 and 0.99995 for L-hyoscyamine and scopolamine, respectively) [15].
• In the other groups of rats, the central anticholinergic agent, l-hyoscyamine, 0.5 mg/kg, was given subcutaneously for premedication before the above-mentioned procedure [16].
• Atropine concentration was determined as l-hyoscyamine equivalents in a radioreceptor assay (RRA) [17].
• Radioimmunoassay for atropine and l-hyoscyamine [13].

References