Influence of group selective reagents in tissues containing α- and β-adrenoceptors

Kadhim N. Salman, Hai S. Chai, Duane Miller, Popat N. Patil

Research output: Contribution to journalArticle

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Abstract

N-ethylmaleimide which is known to react irreversibly with free -SH groups of protein when incubated with rabbit aorta (α-adrenoceptor) or atria (β-adrenoceptor) markedly depressed the dose-response curves of norepinephrine isomers in the aorta but not in atria. Dithiothreitol, a reagent which reduces SS linkages caused a parallel shift of the dose-response curves of both isomers to an equal degree in aorta. However, in atria the reagent drastically and selectively reduced the maximal effects of (+)-norepinephrine and dopamine. This selective alteration of the (+)-isomer by the reagent probably reflects the conformational changes at the β-adrenoreceptor. The concentrations of N-ethylmaleimide and dithiothreitol required to alter the activity of norepinephrine isomers was higher for atria than for aorta. It may be that α-adrenoreceptors are more susceptible than the β-adrenoreceptors on the -SH group selective reagents. In the highest concentration tested, two other reagents, 2,4-dimethoxybenzylamine and N-acetylimidazole, did not influence the activity of the stereoisomers on aorta. In the presence of dithiothreitol, the pharmacologic effects of a noradrenoreceptor stimulant drug, histamine was potentiated on aorta (H1) and not on atria (H2). Results are discussed in the light of similarity and dissimilarity of adrenoreceptors as reflected by the group selective reagents and the stereoisomers.

Original languageEnglish (US)
Pages (from-to)41-48
Number of pages8
JournalEuropean Journal of Pharmacology
Volume36
Issue number1
DOIs
StatePublished - Jan 1 1976
Externally publishedYes

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Adrenergic Receptors
Aorta
Dithiothreitol
Norepinephrine
Stereoisomerism
Ethylmaleimide
Histamine Agents
Dopamine
Rabbits
Proteins

All Science Journal Classification (ASJC) codes

  • Pharmacology

Cite this

Influence of group selective reagents in tissues containing α- and β-adrenoceptors. / Salman, Kadhim N.; Chai, Hai S.; Miller, Duane; Patil, Popat N.

In: European Journal of Pharmacology, Vol. 36, No. 1, 01.01.1976, p. 41-48.

Research output: Contribution to journalArticle

Salman, Kadhim N. ; Chai, Hai S. ; Miller, Duane ; Patil, Popat N. / Influence of group selective reagents in tissues containing α- and β-adrenoceptors. In: European Journal of Pharmacology. 1976 ; Vol. 36, No. 1. pp. 41-48.
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