A Comparison of Cinobufotenine (The Quaternary Derivative of 5‐ht) and Some Related Compounds With Coryneine (The Quaternary Derivative of Dopamine) on the Frog Rectus, Guinea‐pig Ileum and Rat Fundus Strip Preparations

Barlow, R. B.; Burston, K.N.

doi:10.1111/j.1476-5381.1980.tb07909.x

Cited by 8 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To avoid precipitation of phosphates in the more acidic solutions, Burgen reduced the concentrations of calcium and magnesium ions to one-fifth of normal and, for consistency, used these low concentrations over the whole range, even when the buffering system involved Tris or glycine. In previous work (Barlow & Burston, 1980b) we have used these solutions satisfactorily in the more alkaline range on the guinea-pig ileum but when we attempted to use the more acid solutions in this work the responses of the ileum did not appear normal. The contractions faded badly and the tissue was much less sensitive than with ordinary Tyrode solution.…”

Section: Methodsmentioning

confidence: 89%

AFFINITIES OF THE PROTONATED AND NON‐PROTONATED FORMS OF HYOSCINE AND HYOSCINE N‐OXIDE FOR MUSCARINIC RECEPTORS OF THE GUINEA‐PIG ILEUM AND A COMPARISON OF THEIR SIZE IN SOLUTION WITH THAT OF ATROPINE

Barlow¹,

Winter²

1981

British J Pharmacology

Self Cite

View full text Add to dashboard Cite

1 At 37°C in 0.1 M NaCl the pKa of hyoscine (10 mM) is 7.53; the non-protonated form has about one-tenth of the affinity (log K = 8.58) of the protonated form (log K = 9.58) for muscarine-sensitive receptors of the guinea-pig ileum at 37°C.2 In the same conditions the pKa of hyoscine N-oxide is 5.78 and the non-protonated form is inactive on the ileum whereas the protonated form is highly active with log K estimated to be 9.9, at least as active as hyoscine methobromide (log K = 9.85).3 Hyoscine methobromide appears to occupy less space in water than atropine methobromide; hyoscine hydrochloride occupies less space than hyoscyamine hydrochloride: the non-protonated forms are slightly bigger. Hyoscine N-oxide hydrobromide is slightly smaller than hyoscine methobromide but the removal of the proton is accompanied by a reduction in volume, such as is seen with other zwitterions. 4 These differences in volume indicate a reduction in entropy on solution which may allow a greater increase in entropy on binding to receptors and hence greater affinity. The higher activity of hyoscine itself could also be due to the presence of the N-methyl group in the axial position, rather than equatorial as in hyoscyamine or atropine.5 The different position of the N-methyl group may partly explain why the pKa of hyoscine is 2 units lower than that of hyoscyamine or atropine. It is also probable that the unionized form of hyoscine is stabilized by hydration. 6 Although hyoscine N-oxide is only weakly active at pH 7.6, it is present in a highly active form in the acid environment of the stomach and so might be expected to act selectively at this site.

show abstract

Section: Methodsmentioning

confidence: 89%

AFFINITIES OF THE PROTONATED AND NON‐PROTONATED FORMS OF HYOSCINE AND HYOSCINE N‐OXIDE FOR MUSCARINIC RECEPTORS OF THE GUINEA‐PIG ILEUM AND A COMPARISON OF THEIR SIZE IN SOLUTION WITH THAT OF ATROPINE

Barlow¹,

Winter²

1981

British J Pharmacology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Coryneine stimulates adenilyl cyclase in rat brain striatal homogenates and therefore acts like a weak D 1 (or D 1 + D 5 ) dopamine receptor partial agonist [54]. Its effect on rat fundus (5-HT 2B ) serotonin receptors was negligible [55]. Nevertheless, the chances of coryneine, with a second hydroxyl group, evidencing any central effects upon oral dosing seem even more remote than with candicine.…”

Section: Casselsmentioning

confidence: 94%

Alkaloids of the Cactaceae — The Classics

Cassels

2019

Natural Product Communications

View full text Add to dashboard Cite

Alkaloids of the Cactaceae have been studied for the last 120 years. The first half of that period provided the "classic" compounds, after which a large number of usually very similar analogs were isolated or determined with modern methods. Although some unusual synthetic approaches have been developed, their preparation is generally quite straightforward. Their biosynthesis has been studied but, particularly in the case of the isoquinoline compounds, important aspects have not been addressed. Due to its striking effects, the pharmacology of mescaline has been studied more intensely than that of the other phenethylamines present in cacti, followed only by hordenine. The many 1,2,3,4-tetrahydroisoquinoline alkaloids have attracted much less interest and have often been considered practically inactive. Nevertheless, some recorded activities of this group of compounds suggests a need for additional studies, especially in connection with their co-administration with mescaline, as in dried cacti and in beverages prepared from them.

show abstract

“…5-Hydroxy-N,N,N-trimethyltryptamine was found to be a cholinergic agent about 10-fold more powerful than N,N,N-trimethyltryptamine. 14 Considering their pharmacological properties, it was hypothesized that both compounds may represent the arrival point of a biosynthetic pathway aimed to provide Citrus plants with chemical defense against biotic agents. Our observation that leaves and seeds, more frequently attacked by biotic agents, are the plant parts where the highest levels of those compounds were found further suggests that possibility.…”

Section: ■ Introductionmentioning

confidence: 99%

Serotonin 5-O-β-Glucoside and Its N-Methylated Forms in Citrus Genus Plants

Servillo

Giovane

Casale

et al. 2015

J. Agric. Food Chem.

View full text Add to dashboard Cite

Citrus genus is characterized by a specific presence of indole metabolites deriving from the N-methylation of tryptamine and its hydroxylated form, 5-hydroxytryptamine (serotonin), which are likely involved in plant defense mechanisms. In this study, we identified for the first time the occurrence in Citrus plants of serotonin 5-O-β-glucoside and all its N-methylated derivatives, that is, N-methylserotonin 5-O-β-glucoside, N,N-dimethylserotonin (bufotenine) 5-O-β-glucoside, and N,N,N-trimethylserotonin (bufotenidine) 5-O-β-glucoside. The identification of the glucosylated compounds was based on mass spectrometric studies, hydrolysis by glucosidase, and in some cases, comparison to authentic compounds. Beside leaves, the distribution of the glucosylated forms and their aglycones in some Citrus species was evaluated in flavedo, albedo, juice, and seeds. The simultaneous presence of serotonin and its N-methylated derivatives, together with the corresponding glucosylated forms, is consistent with the occurrence of a metabolic pathway, specific for Citrus, aimed at potentiating the defensive response to biotic stress through the optimization of the production and use of the most toxic of such metabolites.

show abstract

A Comparison of Cinobufotenine (The Quaternary Derivative of 5‐ht) and Some Related Compounds With Coryneine (The Quaternary Derivative of Dopamine) on the Frog Rectus, Guinea‐pig Ileum and Rat Fundus Strip Preparations

Cited by 8 publications

References 12 publications

AFFINITIES OF THE PROTONATED AND NON‐PROTONATED FORMS OF HYOSCINE AND HYOSCINE N‐OXIDE FOR MUSCARINIC RECEPTORS OF THE GUINEA‐PIG ILEUM AND A COMPARISON OF THEIR SIZE IN SOLUTION WITH THAT OF ATROPINE

AFFINITIES OF THE PROTONATED AND NON‐PROTONATED FORMS OF HYOSCINE AND HYOSCINE N‐OXIDE FOR MUSCARINIC RECEPTORS OF THE GUINEA‐PIG ILEUM AND A COMPARISON OF THEIR SIZE IN SOLUTION WITH THAT OF ATROPINE

Alkaloids of the Cactaceae — The Classics

Serotonin 5-O-β-Glucoside and Its N-Methylated Forms in Citrus Genus Plants

Contact Info

Product

Resources

About