Premium
Increased serotonin uptake and decreased serotonin metabolism in veins: is there a role in the control of vascular tone and blood pressure?
Author(s) -
Linder A. Elizabeth,
Ni Wei,
Diaz Jessica L.,
Szasz I. Theodora,
Burnett Robert,
Watts Stephanie W.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1239
Subject(s) - pargyline , serotonin , medicine , endocrinology , chemistry , monoamine oxidase , high performance liquid chromatography , monoamine oxidase inhibitor , biology , enzyme , biochemistry , receptor , chromatography
A role for serotonin (5‐hydroxytryptamine; 5‐HT) in cardiovascular regulation has recently been supported after discovery of a functional local 5‐HT system in peripheral arterial smooth muscle. The venous system redistributes blood volume and can significantly alter blood pressure (BP), and the presence of the 5‐HT system in veins has not been investigated. We hypothesized that the 5‐HT system is present and functional in veins as it is in arteries. The presence of 5‐HT [pg/μg protein] (3.8 ± 1.1 vs. 0.2 ± 0.04; P < 0.05) and the 5‐HT metabolite 5‐ hydroxyindole acetic acid (5‐HIAA) [pg/μg protein] (0.6 ± 0.1 vs. 0.36 ± 0.08) was revealed by high performance liquid chromatography (HPLC) in rat vena cava (VC) and in rat aorta (RA), respectively. In rats treated with the monoamine oxidase‐A (MAO‐A) inhibitor pargyline, the enzyme responsible for 5‐HT degradation, no 5‐HIAA was detected in VC and RA. MAO‐A expression was observed in VC and RA by Western Blot. In pargyline‐treated rats, HPLC revealed higher basal 5‐HT levels in VC (5.2 ± 1.5 pg/μg protein) than in RA (0.97 ± 0.2 pg/μg protein). 5‐HT uptake was measured after the tissues were challenged with exogenous 5‐HT (1 μM); uptake was higher in VC (15.9 +/− 1.5 pg/μg protein) than in RA (6.6 ± 1.4 pg/μg protein). The presence of the 5‐HT transporter in VC was observed by immunohistochemistry. The presence of a functional 5‐HT system in VC raises one more question as to the intriguing role of peripheral 5‐HT in the control of vascular tone and consequently BP.