Vascular serotonin 5-hydroxytryptamine2 receptor blockade by LY215840: lack of effect upon neointima formation in balloon-injured rat carotid arteries.

Abstract

5-Hydroxytryptamine (5-HT) is mitogenic for vascular smooth muscle cells, an effect that may result from 5-HT2 receptor activation. After arterial balloon injury, platelet-derived products including 5-HT are delivered to the denuded vessel wall via platelet adhesion/aggregation and degranulation. To assess the role of 5-HT2 receptors in neointima formation, the selective 5-HT2 receptor antagonist LY215840 was infused continuously in rats with osmotic minipumps from 2 days before until 2 weeks after balloon injury to the left common carotid artery, at which time effects upon intimal thickening were examined. Chronic i.v. infusion of LY215840 (25 micrograms/kg/hr) produced a significant, rightward shift (approximately 500-fold) in the 5-HT pressor-response curve in pithed rats determined at 1 hr, 4 days or 16 days after initiation of infusion. Under these conditions, LY215840 had no significant effect upon cross-sectional intimal area determined 2 weeks postballoon injury (0.118 +/- 0.010 vs. 0.114 +/- 0.017 mm2 for vehicle- and LY215840-treated groups, respectively). Furthermore, the cellular density of neointima from LY215840-treated rats was unchanged relative to that of the vehicle group. As a positive control, heparin infusion produced dose-dependent reductions in intimal thickening in this model. At the infusion rate of 0.22 mg/kg/hr, heparin reduced intimal area from a control value of 0.114 +/- 0.015 to 0.025 +/- 0.007 mm2 (P < .05). Thus, extensive blockade of vascular 5-HT2 receptors does not inhibit neointima formation in this model of vascular balloon injury.

• Authors: R F Kauffman, J S Bean, W E Bloomquist, M L Cohen
• Journal: The Journal of pharmacology and experimental therapeutics (J Pharmacol Exp Ther) Vol. 266 Issue 1 Pg. 450-5 (Jul 1993) ISSN: 0022-3565 [Print] United States
• PMID: 8331571 (Publication Type: Journal Article)

Chemical References

• Receptors, Serotonin
• Serotonin Antagonists
• LY 215840
• Heparin
• Lysergic Acid

Topics

• Animals
• Carotid Artery Diseases (etiology, pathology)
• Carotid Artery, Common (drug effects)
• Catheterization (adverse effects)
• Cell Division (drug effects)
• Disease Models, Animal
• Heparin (pharmacology)
• Lysergic Acid (analogs & derivatives, pharmacology)
• Male
• Muscle, Smooth, Vascular (cytology, drug effects)
• Rats
• Rats, Sprague-Dawley
• Receptors, Serotonin (physiology)
• Serotonin Antagonists (pharmacology)
• Tunica Intima (cytology, drug effects)