Effect of isoprostanes on sympathetic neurotransmission in the human isolated iris-ciliary body

S. Olubusayo Awe, Catherine A. Opere, Lydia C. Harris, Afam J. Uketui, Sunny E. Ohia

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Abstract

Isoprostanes (IsoP's) are prostaglandin-like compounds that are derived from free-radical catalyzed peroxidation of arachidonic acid independent of the cyclcooxygenase enzyme. In the present study, we investigated the effect of IsoP's on norepinephrine (NE) release from human isolated iris-ciliary bodies. Isolated human iris-ciliary bodies were prepared for studies of [3H]NE release using the superfusion method. Both 8-iso-prostaglandin F(2α) (F2-IsoP) and the thromboxane (Tx) receptor agonist, U46619 enhanced field- stimulated [3H]NE release from isolated, superfused human iris-ciliary bodies without affecting basal tritium efflux. On the other hand, an equimolar concentration (10 μM) of 8-iso-prostaglandin E2 (E2-IsoP) inhibited evoked [3H]NE overflow. The Tx-receptor antagonist, SQ 29548 blocked the enhancements of electrically-evoked [3H]NE release induced by F2-IsoP and U46619. However, the inhibitory responses elicited by E2-IsoP was not antagonized by SQ 29548. We conclude that IsoP's can produce both excitatory and inhibitory effects on sympathetic neurotransmission in human isolated iris-ciliary bodies. The stimulatory effects of IsoP's on NE release may be mediated by Tx-receptors.

Original languageEnglish (US)
Pages (from-to)491-496
Number of pages6
JournalNeurochemical Research
Volume25
Issue number4
DOIs
StatePublished - Jun 6 2000

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

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