5-HT7, but not 5-HT2B, receptors mediate hypotension in vagosympathectomized rats

Eur J Pharmacol. 2004 Oct 19;502(3):239-42. doi: 10.1016/j.ejphar.2004.08.050.

Abstract

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Hypotension / chemically induced
  • Hypotension / metabolism*
  • Hypotension / physiopathology*
  • Male
  • Rats
  • Rats, Wistar
  • Receptor, Serotonin, 5-HT2B* / physiology
  • Receptors, Serotonin / physiology*
  • Serotonin / analogs & derivatives*
  • Serotonin / pharmacology
  • Serotonin / toxicity
  • Serotonin 5-HT2 Receptor Agonists
  • Serotonin 5-HT2 Receptor Antagonists
  • Serotonin Antagonists / pharmacology
  • Vagotomy*

Substances

  • Receptor, Serotonin, 5-HT2B
  • Receptors, Serotonin
  • Serotonin 5-HT2 Receptor Agonists
  • Serotonin 5-HT2 Receptor Antagonists
  • Serotonin Antagonists
  • serotonin 7 receptor
  • Serotonin
  • 5-carboxamidotryptamine