Reversal of cirazoline- and phenylpropanolamine-induced anorexia by the alpha 1-receptor antagonist prazosin.

Abstract

Phenylpropanolamine (PPA) is a phenethylamine anorectic drug that exerts direct agonist effects predominantly on alpha 1-adrenoceptors, with some alpha 2-adrenergic activity. Microinjections of PPA, as well as the alpha 1-adrenergic receptor agonists cirazoline, methoxamine, and 1-phenylephrine, into rat paraventricular nucleus (PVN) suppress feeding. The present study further evaluates the alpha 1-adrenergic basis of PPA-induced anorexia by examining the effects of systemic injections of the alpha 1-adrenergic antagonist prazosin (PRAZ, 2 and 5 mg/kg, IP) on the anorexia induced by systemic injections of PPA (5, 10, and 20 mg/kg, IP), as well as cirazoline (0.05, 0.1, and 0.2 mg/kg, IP). Although neither PRAZ dose alone altered food intake in the present study, 2 mg/kg PRAZ effectively reversed the feeding-suppressive effects of both PPA and cirazoline. These results strongly support the hypothesis that alpha 1-adrenoceptor stimulation mediates the anorexia induced by drugs such as PPA and cirazoline.

• Authors: P J Wellman, B T Davies
• Journal: Pharmacology, biochemistry, and behavior (Pharmacol Biochem Behav) Vol. 42 Issue 1 Pg. 97-100 (May 1992) ISSN: 0091-3057 [Print] United States
• PMID: 1356275 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adrenergic alpha-Agonists
• Appetite Depressants
• Imidazoles
• Phenylpropanolamine
• cirazoline
• Prazosin

Topics

• Adrenergic alpha-Agonists (pharmacology)
• Animals
• Appetite Depressants (pharmacology)
• Drinking (drug effects)
• Eating (drug effects)
• Imidazoles (antagonists & inhibitors, pharmacology)
• Male
• Phenylpropanolamine (antagonists & inhibitors, pharmacology)
• Prazosin (pharmacology)
• Rats
• Rats, Inbred Strains