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Inverse Agonism and Neutral Antagonism at a Constitutively Active Alpha-1a Adrenoceptor

Overview
Journal Br J Pharmacol
Publisher Wiley
Specialty Pharmacology
Date 2000 Oct 4
PMID 11015306
Citations 12
Authors
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Abstract

We have studied the antagonist action of prazosin and KMD-3213 in a constitutively active mutant of the human alpha-1a adrenoceptor in which Ala(271) was substituted to Thr and was expressed in CHO cells. Inverse agonism was characterized by up-regulation of receptor density, a decrease in basal GTPgammaS binding, and a reduction in basal inositol-1,4,5-trisphosphate (IP(3)) level. According to the above criteria, prazosin acted as an inverse agonist, whilst KMD-3213 behaved as a neutral antagonist. Compared with the wild-type receptor, mutant receptor exhibited single affinity sites for [(3)H]-prazosin, [(3)H]-KMD and the non-radioactive ligands tested, and displayed significantly higher affinities for several agonists but not for the two antagonists. Administration of KMD-3213 to prazosin-treated CHO cells expressing the mutant receptor reversed the inverse agonism of prazosin resulting in rapid increases in cellular IP(3), in intracellular [Ca(2+)] and in the rate of extracellular acidification. These results indicated that a neutral antagonist can reverse the action of an inverse agonist at the receptor site. The distinct properties of inverse agonist and neutral antagonist in affecting receptor function may be important for the clinical use of such antagonists.

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References
1.
Lefkowitz R, Cotecchia S, Samama P, Costa T . Constitutive activity of receptors coupled to guanine nucleotide regulatory proteins. Trends Pharmacol Sci. 1993; 14(8):303-7. DOI: 10.1016/0165-6147(93)90048-O. View

2.
Parma J, Duprez L, Van Sande J, Cochaux P, Gervy C, Mockel J . Somatic mutations in the thyrotropin receptor gene cause hyperfunctioning thyroid adenomas. Nature. 1993; 365(6447):649-51. DOI: 10.1038/365649a0. View

3.
Chidiac P, Hebert T, Valiquette M, Dennis M, Bouvier M . Inverse agonist activity of beta-adrenergic antagonists. Mol Pharmacol. 1994; 45(3):490-9. View

4.
Barker E, WESTPHAL R, Schmidt D, Sanders-Bush E . Constitutively active 5-hydroxytryptamine2C receptors reveal novel inverse agonist activity of receptor ligands. J Biol Chem. 1994; 269(16):11687-90. View

5.
Milano C, Dolber P, Rockman H, Bond R, Venable M, Allen L . Myocardial expression of a constitutively active alpha 1B-adrenergic receptor in transgenic mice induces cardiac hypertrophy. Proc Natl Acad Sci U S A. 1994; 91(21):10109-13. PMC: 44967. DOI: 10.1073/pnas.91.21.10109. View