Characterization of tyramine and octopamine receptors in the insect (Locusta migratoria migratorioides) brain

László Hiripi, Szilveszter Juhos, Roger G.H. Downer

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The kinetic and pharmacological properties of [3H]tyramine and [3H]octopamine binding to membrane preparations of locust (Locusta migratoria migratorioides) brain were studied to characterize the tyramine and octapamine receptors. [3H]Tyramine and [3H]octopamine bind specifically and reversibly to the locust brain membrane with equilibrium achieved after 20 min. The dissociation of [3H]tyramine is monophasic while that of the [3H]octopamine shows a biphasic tendency. Scatchard analysis of the saturation curves reveals a single high affinity binding site for each of tyramine and octopamine. The mean (±S.E.M.) values of Kd and Bmax are 6.11 ± 0.71 nM and 21.45 ± 3.0 fmol/mg tissue for tyramine and 5.65 ± 0.91 nM and 15.0 ± 2.4 fmol/mg tissue for octopamine, respectively. Pharmacological analysis of the binding suggests the presence of both tyramine and octopamine receptors in the locust brain. α-Adrenergic agonists and antagonists have a high affinity to the octopamine but not the tyramine receptor whereas dopaminergic drugs have a higher affinity to the tyramine receptor than the octopamine receptor. No highly effective inhibitors of tyramine binding were identified. The serotonergic blockers, mianserin, LSD, BOL are effective blockers for both tyramine and octopamine receptors, whereas the serotonergic antagonists gramine is more active against the octopamine than the serotonin receptor. The results suggest that a G-protein binding mechanism is involved in the expression of both the tyramine and octopamine effects.

Original languageEnglish
Pages (from-to)119-126
Number of pages8
JournalBrain research
Volume633
Issue number1-2
DOIs
Publication statusPublished - Jan 7 1994

Keywords

  • Binding
  • Brain
  • Insect
  • Receptor
  • [H]Octopamine
  • [H]Tyramine

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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