Serotonin-2B/2C receptors mediate bovine ciliary muscle contraction: Role in intraocular pressure regulation

Sunny E. Ohia, Ya Fatou Njie-Mbye, Jenaye Robinson, Leah Mitchell, Marshalyn McKoy, Catherine A. Opere, Naj A. Sharif

Research output: Contribution to journalArticle

Abstract

Purpose: To study the pharmacological profile of the serotonin (5-hydroxytryptamine [5-HT]) receptor subtype mediating contractions in bovine isolated ciliary muscles. Methods: Ciliary muscle strips were isolated from bovine eyeballs and mounted in organ baths containing aerated (95% O2, 5% CO2) Krebs buffer solution maintained at 37°C. Each muscle strip was attached at 1 end to a Grass Force-displacement Transducer connected to a Polyview Computer System for recording changes in isometric tension. After an equilibration period, ciliary muscle strips were exposed to selective agonists and antagonists of 5-HT receptors. Results: Both selective and nonselective agonists for 5-HT produced concentration-dependent contractions of isolated ciliary muscles with the following rank order of potency: BW723C86>α-methyl-5-HT>MK-212>>8-hydroxy-DPAT>quipazine>R-DOI>>5-HT>>tryptamine. The selective 5-HT2 receptor antagonists, M-100907 (5-HT2A), RS-127445 (5-HT2B), and RS-102221 (5-HT2C), produced noncompetitive inhibition of the contractile effects of selective agonists yielding antagonist potency (pKB) values of 251 ± 27.2 nM (n = 4), 52.5 ± 6.3 nM (n = 4), and 79.4 ± 9.5 nM (n = 4), respectively. Conclusion: On the basis of the profile of activity of selective agonists and antagonists, we conclude that the 5-HT2B and 5-HT2C receptor subtypes appear to be the predominant serotonin receptors that mediate the contractile action of this amine in bovine isolated ciliary muscles.

Original languageEnglish (US)
Pages (from-to)70-75
Number of pages6
JournalJournal of Ocular Pharmacology and Therapeutics
Volume34
Issue number1-2
DOIs
StatePublished - Jan 1 2018

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Pharmacology
  • Pharmacology (medical)

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