5-Hydroxytryptamine(1F) receptors do not participate in vasoconstriction: lack of vasoconstriction to LY344864, a selective serotonin(1F) receptor agonist in rabbit saphenous vein.

Abstract

Recently, several novel approaches to the treatment of migraine have been advanced, including selective 5-hydroxytryptamine (or serotonin) 1B/1D (5-HT(1B/1D)) receptor agonists such as sumatriptan and 5-HT(1F) receptor agonists such as LY344864. Many 5-HT(1B/1D) receptor agonists have been identified based on their ability to produce cerebral vascular contraction, whereas LY344864 was identified as an inhibitor of trigeminal nerve-mediated dural extravasation. In our study, several triptan derivatives were compared with LY344864 for their ability to contract the rabbit saphenous vein, a tissue used in the preclinical identification of sumatriptan-related agonists. Sumatriptan, zolmitriptan, rizatriptan, and naratriptan all contracted the rabbit saphenous vein from baseline tone, whereas LY344864 in concentrations up to 10(-4) M did not contract the rabbit saphenous vein. Furthermore, vascular contractions to sumatriptan were markedly augmented in the presence of prostaglandin F(2alpha) (PGF(2alpha)). However, even in the presence of PGF(2alpha) (3 x 10(-7) M), LY344864 did not contract the rabbit saphenous vein in concentrations well in excess of its 5-HT(1F) receptor affinity (pK(i) = 8.2). Only when concentrations exceeded those likely to activate 5-HT(1B) and 5-HT(1D) receptors (>10(-5) M) did modest contractile responses occur in the presence of PGF(2alpha). Use of these serotonergic agonists revealed a significant correlation between the contractile potency in the rabbit saphenous vein and the affinities of these agonists at 5-HT(1B) and 5-HT(1D) receptors, although contractile agonist potencies were not quantitatively similar to 5-HT(1B) or 5-HT(1D) receptor affinities. In contrast, no significant correlation existed between the contractile potencies of these serotonergic agonists in the rabbit saphenous vein and their affinity at 5-HT(1F) receptors. These data support the contention that activation of 5-HT(1F) receptors will not result in vascular contractile effects.

• Authors: M L Cohen, K Schenck
• Journal: The Journal of pharmacology and experimental therapeutics (J Pharmacol Exp Ther) Vol. 290 Issue 3 Pg. 935-9 (Sep 1999) ISSN: 0022-3565 [Print] United States
• PMID: 10454462 (Publication Type: Journal Article)

Chemical References

• Carbazoles
• Fluorobenzenes
• LY 344864
• Receptors, Serotonin
• Serotonin Receptor Agonists
• serotonin 1F receptor

Topics

• Animals
• Carbazoles (metabolism, pharmacology)
• Dose-Response Relationship, Drug
• Fluorobenzenes (metabolism, pharmacology)
• In Vitro Techniques
• Kinetics
• Male
• Muscle Contraction (drug effects, physiology)
• Muscle, Smooth, Vascular (drug effects, physiology)
• Protein Binding
• Rabbits
• Radioligand Assay
• Receptors, Serotonin (classification, metabolism, physiology)
• Saphenous Vein (drug effects, physiology)
• Serotonin Receptor Agonists (metabolism, pharmacology)
• Substrate Specificity
• Vasoconstriction (drug effects, physiology)