5-HT7, but not 5-HT2B, receptors mediate hypotension in vagosympathectomized rats.
This study evaluated the possible involvement of 5-HT(2B) receptors in long-lasting hypotension to 5-hydroxytryptamine (5-HT), which is predominantly mediated by 5-HT7 receptors, in anaesthetised vagosympathectomized rats. Intravenous injections of 5-HT and 5-carboxamidotryptamine (5-CT) elicited a dose-dependent hypotension that was dose-dependently antagonised by (R)-1-[(3-hydroxyphenyl)sulfonyl]-2-[2-(4-methyl-1-piperidinyl) ethyl] pyrrolidine (SB-269970; a selective 5-HT7 receptor antagonist), but not by saline. Interestingly, alpha-methyl-5-(2-thienylmethoxy)-1H-indole-3-ethanamine (BW723C86; a 5-HT(2B) receptor agonist) produced vasopressor responses without affecting hypotension to 5-HT. These results suggest that hypotension to 5-HT and 5-CT is mainly mediated by 5-HT7 receptors, whilst the role of 5-HT(2B) receptors seems unlikely.
Departamento de Farmacobiología, CINVESTAV-IPN, Czda. Tenorios 235, Col. Granjas-Coapa, México DF 14330, Mexico.
David
D
Centurión
Erika
E
Glusa
Araceli
A
Sánchez-López
Luis F
LF
Valdivia
Pramod R
PR
Saxena
Carlos M
CM
Villalón
D000818:Animals; D004305:Dose-Response Relationship, Drug; D007022:Hypotension / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D044403:Receptor, Serotonin, 5-HT2B / Q000502:physiology; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000633:toxicity; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D012702:Serotonin Antagonists / Q000494:pharmacology; D014628:Vagotomy
D044403:Receptor, Serotonin, 5-HT2B; D011985:Receptors, Serotonin; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D012702:Serotonin Antagonists; C104425:serotonin 7 receptor; D012701:Serotonin; C047087:5-carboxamidotryptamine