| Autor: |
Inoue-Matsuhisa, Eri, Moroi, Sayoko E., Takenaka, Hisashi, Sogo, Shunji, Mano, Tomiya |
| Předmět: |
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| Zdroj: |
Journal of Ocular Pharmacology & Therapeutics; Feb2003, Vol. 19 Issue 1, p55-62, 8p |
| Abstrakt: |
The serotonin 2 (5-HT[sub 2]) receptor antagonists, MCI-9042 (Anplag[sup ®]) and ketanserin, have been shown to lower intraocular pressure in rabbits (1) and humans (2). The mechanism of action of these drugs has not been determined, but it is hypothesized that 5-HT[sub 2] receptors, and possibly α-adrenergic receptors, (3) may regulate in part aqueous humor production via an intracellular signal transduction pathway in the ciliary body. We therefore examined whether 5-HT[sub 2] receptors were coupled to phosphoinositide hydrolysis in an organ culture system of isolated bovine ciliary epithelium. 5-HT stimulated [[sup 3]H]inositol phosphates ([[sup 3]H]InsPs) accumulation in a dose-dependent manner with a maximum increase approximately twice over the basal level. The mean EC[sub 50] value was 1.1 μM, which was calculated from four dose-response curves. The 5-HT stimulated accumulation of [[sup 3]H]InsPs was inhibited by spiperone (5-HT[sub 2A/1A] and dopamine 2 (D[sub 2]) antagonists), M-1 (a major metabolite of MCI-9042), ketanserin (5-HT[sub 2A] antagonist), SB-206553 (5- HT[sub 2B/2C] antagonist), and mesulergine (5-HT[sub 2C] antagonist and D[sub 2] agonist). It was not inhibited by chlorpromazine, which is a D[sub 2] receptor antagonist. Accordingly, our study demonstrates that 5-HT[sub 2] receptors are coupled to phospholipase C in bovine ciliary epithelium. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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