Alpha 2-adrenoceptor blocking properties of idazoxan stereoisomers: stereoselectivity for presynaptic alpha 2-adrenoceptors

Maria Martire, Paolo Preziosi, G Pistritto

Research output: Contribution to journalArticlepeer-review

Abstract

The alpha 2-adrenoceptor blocking properties of idazoxan enantiomers were evaluated at pre- and postsynaptic level. The antagonism of the two idazoxan stereoisomers was assessed, at presynaptic level, by their ability to antagonize clonidine at the alpha 2-adrenoceptors regulating noradrenaline release. The antagonist (+)-idazoxan showed an affinity towards the alpha 2-autoreceptors 40 times higher than that showed by (-)-idazoxan. Binding studies revealed (+)-idazoxan to be 7-8 times more potent than (-)-idazoxan in inhibiting the p-[3H]aminoclonidine binding. These results indicate a different affinity of alpha 2-adrenoceptors for the two idazoxan stereoisomers, thus suggesting that the alpha 2-adrenoceptors located pre- and postsynaptically may be of two stereochemically different subtypes.
Original languageEnglish
Pages (from-to)328-333
Number of pages6
JournalNeuroscience Letters
Volume86
Publication statusPublished - 1988

Keywords

  • Animals
  • Binding, Competitive
  • Cerebral Cortex
  • Clonidine
  • Dioxanes
  • Dioxins
  • Hypothalamus
  • Idazoxan
  • Male
  • Norepinephrine
  • Rats
  • Rats, Inbred Strains
  • Receptors, Adrenergic, alpha
  • Stereoisomerism
  • Synaptosomes

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