title: Lack of the serotonin transporter (SERT) reduces the ability of 5-hydroxytryptamine to lower blood pressure.
abstract: Serotonin (5-hydroxytryptamine; 5-HT) is a potent constrictor of isolated blood vessels. However, recent studies demonstrate that chronic 5-HT infusion results in a prolonged fall in blood pressure in the rat. This finding highlights the need for further study of 5-HT in the cardiovascular system. We tested the hypothesis that a functional serotonin transporter (SERT) is critical to enabling a 5-HT-induced fall in blood pressure. Experiments were performed in male and female rats to determine whether gender significantly affected the ability of 5-HT to lower blood pressure and to determine whether SERT dependence was different in male vs. female rats. 5-HT (25 μg/kg/min; s.c.) was infused for 7 days to male and female, SERT wild-type (WT) and SERT knockout (KO) rats. Mean arterial pressure (MAP) and heart rate were monitored via radiotelemetry. 5-HT produced a significantly greater fall in MAP (at the nadir) in the male SERT WT rat (-20 ± 1 mmHg) compared to the male SERT KO rat (-10 ± 2 mmHg). Similarly, 5-HT also produced a significantly greater fall in MAP (at the nadir) in the female SERT WT rat (-19 ± 1 mmHg) compared to the female SERT KO rat (-15 ± 0.4 mmHg). While the lack of a functional SERT protein did not prevent a 5-HT-induced fall in blood pressure, it did reduce the ability of 5-HT to lower blood pressure in the male and female SERT rat, suggesting a potentially important role for SERT in producing a 5-HT-induced fall in blood pressure.
authors: Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824-1317, USA. davisr15@msu.edu
authors: Robert
authors: R
authors: Patrick Davis
authors: A Elizabeth
authors: AE
authors: Linder
authors: Stephanie W
authors: SW
authors: Watts
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D015153:Blotting, Western; D003627:Data Interpretation, Statistical; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D011922:Rats, Mutant Strains; D017208:Rats, Wistar; D012701:Serotonin / Q000097:blood / Q000494:pharmacology* / Q000502:physiology; D050486:Serotonin Plasma Membrane Transport Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D012727:Sex Characteristics
chemical_list: D050486:Serotonin Plasma Membrane Transport Proteins; C493232:Slc6a4 protein, rat; D012701:Serotonin