Pharmacology of serotonin receptors causing contraction of isolated bovine posterior ciliary arteries

Role in ocular blood flow

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

Research output: Contribution to journalArticle

Abstract

Purpose: To determine the serotonergic (5HT) receptor subtype mediating the contraction of bovine posterior ciliary arteries (BPCAs) in vitro. Methods: Longitudinal isometric tension was measured in BPCA strips (4-5 mm) mounted in 25 mL organ baths containing oxygenated Krebs solution at 37°C. Cumulative contractile concentration-response (C-R) curves were generated for various 5-HT agonists to assess their potencies and maximal degrees of contraction. Multiple agonist C-R curves were also constructed in the presence and absence of receptor-selective antagonists to determine antagonist potencies using Schild plots. Results: Selective and nonselective agonists for 5-HT receptors elicited concentration-dependent contractile responses in BPCAs with the following rank order of potency: MK-212 > BW723C86 > α-methyl-5-HT >5-methoxy-α-5-methyl-5-HT >> R-DO1 > >5-HT >> cabergoline >> 5-methoxy-dimethyl-tryptamine >> 2-methyl-5-HT >> tryptamine. Interestingly, both 8-OH-DPAT (5HT1A agonist) and quipazine (5HT3 agonist) did not elicit contractions in BPCAs. The contractions produced by BW723C86 (5-HT2B agonist) were antagonized by 5-HT receptor blockers, RS-127445 (5-HT2B antagonist), and M-100907 (5-HT2A antagonist), yielding antagonist pA2 values of 7.5 ± 0.12 (n = 4) and 6.2 ± 0.17 (n = 4), respectively. Furthermore, contractions elicited by MK-212 (5-HT2C agonist) was blocked by RS-102221 (5-HT2C antagonist), although noncompetitively. Conclusions: On the basis of the pharmacological profile of selective agonists and antagonists, we conclude that serotonin-induced contractions of the BPCA are mediated primarily by a combination of 5HT2C and/or 5HT2B receptors. It appears that 5-HT1A and 5-HT3 receptors are not involved in the contractile action of BPCAs to serotonin.

Original languageEnglish (US)
Pages (from-to)134-140
Number of pages7
JournalJournal of Ocular Pharmacology and Therapeutics
Volume34
Issue number1-2
DOIs
StatePublished - Jan 1 2018

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Ciliary Arteries
Serotonin Receptors
Pharmacology
Serotonin 5-HT2 Receptor Antagonists
Serotonin
Serotonin 5-HT2 Receptor Agonists
Quipazine
Receptors, Serotonin, 5-HT3
8-Hydroxy-2-(di-n-propylamino)tetralin
Serotonin Receptor Agonists
Serotonin Antagonists
Baths

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Pharmacology
  • Pharmacology (medical)

Cite this

Pharmacology of serotonin receptors causing contraction of isolated bovine posterior ciliary arteries : Role in ocular blood flow. / Njie-Mbye, Ya Fatou; Robinson, Jenaye; Mitchell-Bush, Leah; McKoy, Marshalyn; Opere, Catherine A.; Ohia, Sunny E.; Sharif, Naj.

In: Journal of Ocular Pharmacology and Therapeutics, Vol. 34, No. 1-2, 01.01.2018, p. 134-140.

Research output: Contribution to journalArticle

Njie-Mbye, Ya Fatou ; Robinson, Jenaye ; Mitchell-Bush, Leah ; McKoy, Marshalyn ; Opere, Catherine A. ; Ohia, Sunny E. ; Sharif, Naj. / Pharmacology of serotonin receptors causing contraction of isolated bovine posterior ciliary arteries : Role in ocular blood flow. In: Journal of Ocular Pharmacology and Therapeutics. 2018 ; Vol. 34, No. 1-2. pp. 134-140.
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abstract = "Purpose: To determine the serotonergic (5HT) receptor subtype mediating the contraction of bovine posterior ciliary arteries (BPCAs) in vitro. Methods: Longitudinal isometric tension was measured in BPCA strips (4-5 mm) mounted in 25 mL organ baths containing oxygenated Krebs solution at 37°C. Cumulative contractile concentration-response (C-R) curves were generated for various 5-HT agonists to assess their potencies and maximal degrees of contraction. Multiple agonist C-R curves were also constructed in the presence and absence of receptor-selective antagonists to determine antagonist potencies using Schild plots. Results: Selective and nonselective agonists for 5-HT receptors elicited concentration-dependent contractile responses in BPCAs with the following rank order of potency: MK-212 > BW723C86 > α-methyl-5-HT >5-methoxy-α-5-methyl-5-HT >> R-DO1 > >5-HT >> cabergoline >> 5-methoxy-dimethyl-tryptamine >> 2-methyl-5-HT >> tryptamine. Interestingly, both 8-OH-DPAT (5HT1A agonist) and quipazine (5HT3 agonist) did not elicit contractions in BPCAs. The contractions produced by BW723C86 (5-HT2B agonist) were antagonized by 5-HT receptor blockers, RS-127445 (5-HT2B antagonist), and M-100907 (5-HT2A antagonist), yielding antagonist pA2 values of 7.5 ± 0.12 (n = 4) and 6.2 ± 0.17 (n = 4), respectively. Furthermore, contractions elicited by MK-212 (5-HT2C agonist) was blocked by RS-102221 (5-HT2C antagonist), although noncompetitively. Conclusions: On the basis of the pharmacological profile of selective agonists and antagonists, we conclude that serotonin-induced contractions of the BPCA are mediated primarily by a combination of 5HT2C and/or 5HT2B receptors. It appears that 5-HT1A and 5-HT3 receptors are not involved in the contractile action of BPCAs to serotonin.",
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T1 - Pharmacology of serotonin receptors causing contraction of isolated bovine posterior ciliary arteries

T2 - Role in ocular blood flow

AU - Njie-Mbye, Ya Fatou

AU - Robinson, Jenaye

AU - Mitchell-Bush, Leah

AU - McKoy, Marshalyn

AU - Opere, Catherine A.

AU - Ohia, Sunny E.

AU - Sharif, Naj

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N2 - Purpose: To determine the serotonergic (5HT) receptor subtype mediating the contraction of bovine posterior ciliary arteries (BPCAs) in vitro. Methods: Longitudinal isometric tension was measured in BPCA strips (4-5 mm) mounted in 25 mL organ baths containing oxygenated Krebs solution at 37°C. Cumulative contractile concentration-response (C-R) curves were generated for various 5-HT agonists to assess their potencies and maximal degrees of contraction. Multiple agonist C-R curves were also constructed in the presence and absence of receptor-selective antagonists to determine antagonist potencies using Schild plots. Results: Selective and nonselective agonists for 5-HT receptors elicited concentration-dependent contractile responses in BPCAs with the following rank order of potency: MK-212 > BW723C86 > α-methyl-5-HT >5-methoxy-α-5-methyl-5-HT >> R-DO1 > >5-HT >> cabergoline >> 5-methoxy-dimethyl-tryptamine >> 2-methyl-5-HT >> tryptamine. Interestingly, both 8-OH-DPAT (5HT1A agonist) and quipazine (5HT3 agonist) did not elicit contractions in BPCAs. The contractions produced by BW723C86 (5-HT2B agonist) were antagonized by 5-HT receptor blockers, RS-127445 (5-HT2B antagonist), and M-100907 (5-HT2A antagonist), yielding antagonist pA2 values of 7.5 ± 0.12 (n = 4) and 6.2 ± 0.17 (n = 4), respectively. Furthermore, contractions elicited by MK-212 (5-HT2C agonist) was blocked by RS-102221 (5-HT2C antagonist), although noncompetitively. Conclusions: On the basis of the pharmacological profile of selective agonists and antagonists, we conclude that serotonin-induced contractions of the BPCA are mediated primarily by a combination of 5HT2C and/or 5HT2B receptors. It appears that 5-HT1A and 5-HT3 receptors are not involved in the contractile action of BPCAs to serotonin.

AB - Purpose: To determine the serotonergic (5HT) receptor subtype mediating the contraction of bovine posterior ciliary arteries (BPCAs) in vitro. Methods: Longitudinal isometric tension was measured in BPCA strips (4-5 mm) mounted in 25 mL organ baths containing oxygenated Krebs solution at 37°C. Cumulative contractile concentration-response (C-R) curves were generated for various 5-HT agonists to assess their potencies and maximal degrees of contraction. Multiple agonist C-R curves were also constructed in the presence and absence of receptor-selective antagonists to determine antagonist potencies using Schild plots. Results: Selective and nonselective agonists for 5-HT receptors elicited concentration-dependent contractile responses in BPCAs with the following rank order of potency: MK-212 > BW723C86 > α-methyl-5-HT >5-methoxy-α-5-methyl-5-HT >> R-DO1 > >5-HT >> cabergoline >> 5-methoxy-dimethyl-tryptamine >> 2-methyl-5-HT >> tryptamine. Interestingly, both 8-OH-DPAT (5HT1A agonist) and quipazine (5HT3 agonist) did not elicit contractions in BPCAs. The contractions produced by BW723C86 (5-HT2B agonist) were antagonized by 5-HT receptor blockers, RS-127445 (5-HT2B antagonist), and M-100907 (5-HT2A antagonist), yielding antagonist pA2 values of 7.5 ± 0.12 (n = 4) and 6.2 ± 0.17 (n = 4), respectively. Furthermore, contractions elicited by MK-212 (5-HT2C agonist) was blocked by RS-102221 (5-HT2C antagonist), although noncompetitively. Conclusions: On the basis of the pharmacological profile of selective agonists and antagonists, we conclude that serotonin-induced contractions of the BPCA are mediated primarily by a combination of 5HT2C and/or 5HT2B receptors. It appears that 5-HT1A and 5-HT3 receptors are not involved in the contractile action of BPCAs to serotonin.

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