Effects of oxymorphazone in frogs

Long lasting antinociception in vivo, and apparently irreversible binding in vitro

S. Benyhe, Gy Hoffmann, E. Varga, S. Hosztafi, G. Toth, A. Borsodi, M. Wollemann

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Oxymorphazone (at doses of 50-200 mg/kg) was found to be a relatively weak antinociceptive drug in intact frog (Rana esculenta) when acetic acid was used as pain stimulus. Frogs remained analgesic for at least 48 hrs following oxymorphazone (200 mg/kg) administration. The ligand increased the latency of wiping reflex in spinal frogs too. These effects were blocked by naloxone. In equilibrium binding studies (3H) oxymorphazone had high affinity to the opioid receptors of frog brain and spinal cord as well (apparent Kd values were 8.9 and 10.6 nM, respectively). Kinetic experiments show that only 25 % of the bound (3H) oxymorphazone is readily dissociable. Preincubation of the membranes with labeled oxymorphazone results in a washing resistant inhibition of the opioid binding sites. At least 70 % of the (3H) oxymorphazone specific binding is apparently irreversible after reaction at 5 nM ligand concentration, and this can be enhanced by a higher concentration of tritiated ligand.

Original languageEnglish
Pages (from-to)1847-1857
Number of pages11
JournalLife Sciences
Volume44
Issue number24
DOIs
Publication statusPublished - 1989

Fingerprint

Anura
Ligands
Rana esculenta
Opioid Receptors
Naloxone
Washing
Acetic Acid
Opioid Analgesics
Reflex
Analgesics
oxymorphazone
In Vitro Techniques
Brain
Spinal Cord
Binding Sites
Membranes
Pain
Kinetics
Pharmaceutical Preparations
Experiments

ASJC Scopus subject areas

  • Pharmacology

Cite this

Effects of oxymorphazone in frogs : Long lasting antinociception in vivo, and apparently irreversible binding in vitro. / Benyhe, S.; Hoffmann, Gy; Varga, E.; Hosztafi, S.; Toth, G.; Borsodi, A.; Wollemann, M.

In: Life Sciences, Vol. 44, No. 24, 1989, p. 1847-1857.

Research output: Contribution to journalArticle

Benyhe, S. ; Hoffmann, Gy ; Varga, E. ; Hosztafi, S. ; Toth, G. ; Borsodi, A. ; Wollemann, M. / Effects of oxymorphazone in frogs : Long lasting antinociception in vivo, and apparently irreversible binding in vitro. In: Life Sciences. 1989 ; Vol. 44, No. 24. pp. 1847-1857.
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