Piglet sinoatrial 5-HT receptors resemble human atrial 5-HT4-like receptors.

Abstract

5-Hydroxytryptamine (5-HT), 5-carboxamidotryptamine (5-CT) and the gastrointestinal kinetic benzamides renzapride and cisapride caused tachycardia in spontaneously beating right atria of piglet in the presence of 400 nmol/l (+/-)-propranolol and 6 mumol/l cocaine. The maximum tachycardia caused by agonists, compared to that evoked by 200 mumol/l (-)-isoprenaline, was 63% for 5-HT, 50% for 5-CT, 50% for renzapride and 28% for cisapride. The rank order of potency was 5-HT greater than renzapride greater than cisapride greater than 5-CT. The effects of the agonists, but not those of (-)-isoprenaline, were antagonised by 3 alpha-tropanyl-1H-indole-3-carboxylic acid (ICS 205930); the pKB of ICS 205930 (vs 5-HT) was 6.9. These characteristics suggest that piglet sinoatrial 5-HT receptors are similar to "so-called" 5-HT4 receptors previously described in mouse colliculi neurons. Piglet sinoatrial 5-HT4-like receptors resemble the human atrial 5-HT receptors that mediate positive inotropic effects of 5-HT.

• Authors: A J Kaumann
• Journal: Naunyn-Schmiedeberg's archives of pharmacology (Naunyn Schmiedebergs Arch Pharmacol) Vol. 342 Issue 5 Pg. 619-22 (Nov 1990) ISSN: 0028-1298 [Print] Germany
• PMID: 2090956 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Benzamides
• Bridged Bicyclo Compounds
• Bridged Bicyclo Compounds, Heterocyclic
• Cardiotonic Agents
• Indoles
• Piperidines
• Receptors, Serotonin
• Serotonin Antagonists
• Serotonin
• Tropisetron
• renzapride
• 5-carboxamidotryptamine
• Cisapride

Topics

• Animals
• Benzamides (pharmacology)
• Bridged Bicyclo Compounds (pharmacology)
• Bridged Bicyclo Compounds, Heterocyclic
• Cardiotonic Agents (pharmacology)
• Cisapride
• Female
• Heart (drug effects)
• Heart Atria (drug effects)
• Humans
• In Vitro Techniques
• Indoles (pharmacology)
• Male
• Piperidines (pharmacology)
• Receptors, Serotonin (classification, drug effects)
• Serotonin (analogs & derivatives, pharmacology)
• Serotonin Antagonists (pharmacology)
• Sinoatrial Node (drug effects)
• Swine
• Tropisetron