Identification of dopamine receptor subtypes in the hypotensive action of SK&F 85174 in anesthetized rats.

Abstract

1 We have performed experiments to determine the effect of SK&F 85174 on blood pressure in anaesthetized rats and identify dopamine receptor subtype(s) involved in its action. 2 SK&F 85174 decreased blood pressure in a dose-related manner. There were no significant changes in heart rate. The hypotensive action was short-lasting and was significantly antagonized by the selective DA1-receptor antagonist. SCH 23390 (100 micrograms/kg). This dose of SCH 23390 did not alter the hypotension produced by the DA2-receptor agonist, quinpirole. 3 The DA2-receptor antagonist, domperidone (25 micrograms/kg), did not significantly alter the hypotension produced by lower doses of SK&F 85174, but antagonized the hypotensive action of the highest dose of SK&F 85174 by about 35%. This dose of domperidone antagonized the hypotension produced by quinpirole by 85% without affecting the hypotensive action of the DA1-receptor agonist, fenoldopam. 4 These results show that at lower doses of SK&F 85174, the hypotension is due primarily to DA1-receptor activation, whereas DA2-receptor activation may also contribute to the blood pressure decrease produced by higher doses of SK&F 85174.

• Authors: B A Sowinski, M F Lokhandwala
• Journal: Journal of autonomic pharmacology (J Auton Pharmacol) Vol. 7 Issue 2 Pg. 105-9 (Jun 1987) ISSN: 0144-1795 [Print] England
• PMID: 2888767 (Publication Type: Journal Article)

Chemical References

• Antipsychotic Agents
• Benzazepines
• Ergolines
• Receptors, Dopamine
• Quinpirole
• Domperidone
• SK&F 85174

Topics

• Anesthesia
• Animals
• Antipsychotic Agents (pharmacology)
• Benzazepines (pharmacology)
• Blood Pressure (drug effects)
• Domperidone (pharmacology)
• Ergolines (pharmacology)
• Heart Rate (drug effects)
• Male
• Quinpirole
• Rats
• Rats, Inbred Strains
• Receptors, Dopamine (drug effects)