BACKGROUND AND PURPOSE: 5-HT is a vasoconstrictor exhibiting enhanced effects in systemic arteries from subjects with cardiovascular disease. The effect of endogenous 5-HT on arteries is controversial, because the concentration of free circulating 5-HT is low and a 5-hydroxytryptaminergic system has not been identified in peripheral arteries. We hypothesized that a local 5-hydroxytryptaminergic system (including 5-HT synthesis, metabolism, uptake and release) with physiological function exists in peripheral arteries. EXPERIMENTAL APPROACH: The presence of key components of a 5-hydroxytryptaminergic system in rat aorta and superior mesenteric artery was examined using western blot analyses, immunohistochemistry and immunocytochemistry. The function of the rate-limiting enzyme in 5-HT biosynthesis, tryptophan hydroxylase (TPH), and 5-HT transporter was tested by measuring enzyme activity and 5-HT uptake, respectively. Isometric contraction of arterial strips was used to demonstrate the function of released endogenous 5-HT in arterial tissues. KEY RESULTS: mRNA for TPH-1 was present in arteries, with low levels of TPH protein and TPH activity. Expression and function of MAO A (5-HT metabolizing enzyme) was supported by immunohistochemistry, western analyses and the elevation of concentrations of 5-hydroxyindoleacetic acid (5-HT metabolite) after exposure to exogenous 5-HT. The 5-HT transporter was localized to the plasma membrane of freshly isolated aortic smooth muscle cells. Peripheral arteries actively took up 5-HT in a time-dependent and 5-HT transporter-dependent manner. The 5-HT transporter substrate, (+)-fenfluramine, released endogenous 5-HT from peripheral arteries, which potentiated noradrenaline-induced arterial contraction. CONCLUSIONS AND IMPLICATIONS: This study revealed the existence of a local 5-hydroxytryptaminergic system in peripheral arteries.
BACKGROUND AND PURPOSE: 5-HT is a vasoconstrictor exhibiting enhanced effects in systemic arteries from subjects with cardiovascular disease. The effect of endogenous 5-HT on arteries is controversial, because the concentration of free circulating 5-HT is low and a 5-hydroxytryptaminergic system has not been identified in peripheral arteries. We hypothesized that a local 5-hydroxytryptaminergic system (including 5-HT synthesis, metabolism, uptake and release) with physiological function exists in peripheral arteries. EXPERIMENTAL APPROACH: The presence of key components of a 5-hydroxytryptaminergic system in rat aorta and superior mesenteric artery was examined using western blot analyses, immunohistochemistry and immunocytochemistry. The function of the rate-limiting enzyme in 5-HT biosynthesis, tryptophan hydroxylase (TPH), and 5-HT transporter was tested by measuring enzyme activity and 5-HT uptake, respectively. Isometric contraction of arterial strips was used to demonstrate the function of released endogenous 5-HT in arterial tissues. KEY RESULTS: mRNA for TPH-1 was present in arteries, with low levels of TPH protein and TPH activity. Expression and function of MAO A (5-HT metabolizing enzyme) was supported by immunohistochemistry, western analyses and the elevation of concentrations of 5-hydroxyindoleacetic acid (5-HT metabolite) after exposure to exogenous 5-HT. The 5-HT transporter was localized to the plasma membrane of freshly isolated aortic smooth muscle cells. Peripheral arteries actively took up 5-HT in a time-dependent and 5-HT transporter-dependent manner. The 5-HT transporter substrate, (+)-fenfluramine, released endogenous 5-HT from peripheral arteries, which potentiated noradrenaline-induced arterial contraction. CONCLUSIONS AND IMPLICATIONS: This study revealed the existence of a local 5-hydroxytryptaminergic system in peripheral arteries.
Authors: P A Robiolio; V H Rigolin; J S Wilson; J K Harrison; L L Sanders; T M Bashore; J M Feldman Journal: Circulation Date: 1995-08-15 Impact factor: 29.690
Authors: Kyle B Johnson; Humphrey Petersen-Jones; Janice M Thompson; Kiyotaka Hitomi; Miho Itoh; Erik N T P Bakker; Gail V W Johnson; Gozde Colak; Stephanie W Watts Journal: Am J Physiol Heart Circ Physiol Date: 2012-02-03 Impact factor: 4.733
Authors: Yasmine Chabbi-Achengli; Amélie E Coudert; Jacques Callebert; Valérie Geoffroy; Francine Côté; Corinne Collet; Marie-Christine de Vernejoul Journal: Proc Natl Acad Sci U S A Date: 2012-01-30 Impact factor: 11.205
Authors: A Elizabeth Linder; Geri L Gaskell; Theodora Szasz; Janice M Thompson; Stephanie W Watts Journal: J Pharmacol Exp Ther Date: 2010-04-08 Impact factor: 4.030