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

doi:10.1023/A:1007560025570

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

Department of Pharmacy Sciences

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18 Scopus citations

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 language	English (US)
Pages (from-to)	491-496
Number of pages	6
Journal	Neurochemical Research
Volume	25
Issue number	4
DOIs	https://doi.org/10.1023/A:1007560025570
State	Published - Jun 6 2000

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All Science Journal Classification (ASJC) codes

Biochemistry
Cellular and Molecular Neuroscience

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Awe, S. O., Opere, C. A., Harris, L. C., Uketui, A. J., & Ohia, S. E. (2000). Effect of isoprostanes on sympathetic neurotransmission in the human isolated iris-ciliary body. Neurochemical Research, 25(4), 491-496. https://doi.org/10.1023/A:1007560025570

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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.",

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AU - Awe, S. Olubusayo

AU - Opere, Catherine A.

AU - Harris, Lydia C.

AU - Uketui, Afam J.

AU - Ohia, Sunny E.

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N2 - 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.

AB - 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.

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10.1023/A:1007560025570