Therapeutic implications of constitutive activity of receptors: the example of the histamine H3 receptor
Some G-protein-coupled receptors display constitutive activity, that is spontaneous activity in the absence of agonist: a proportion of the receptor population adopts a conformation that can bind and activate G proteins. Whereas this was mainly shown to occur with recombinant or pathologically mutated receptors, the physiological relevance of the process has remained debated. We have adressed this question in the case of the histamine H3 receptor, a presynaptic inhibitory receptor regulating histamine release in brain. Having identified a neutral antagonist and inverse agonists with variable intrinsic activity, we show that the native H3 receptor in brain displays high constitutive activity in vitro and, in vivo, controls the release of endogenous histamine. This implies that inverse agonists with high intrinsic activity should be preferred for therapeutic application as “cognitive enhancers” in several psychiatric disorders.
KeywordsHistamine Release Constitutive Activity Inverse Agonist Arachidonic Acid Release Neutral Antagonist
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- Kenakin TP (1997) Pharmacological analysis of drug receptor interaction. Lippincott-Raven, New YorkGoogle Scholar
- Prell GD, Green JP, Kaufmann CA, Khandelwal JK, Morrishow AM, Kirch DG, Linnoila M, Wyatt RJ (1995) Histamine metabolites in cerebrospinal fluid of patients with chronic schizophrenia: their relationship to levels of other aminergic transmitters and ratings of symptoms. Schizophr Res 14: 93–104PubMedCrossRefGoogle Scholar
- Authors’ address: J.-C. Schwartz, Unit¨¦ de Neurobiologie et Pharmacologie Mol¨¦culaire (U.573) INSERM, Centre Paul Broca, 2ter rue d’Al¨¦sia, F-75014 Paris, France, e-mail: email@example.comGoogle Scholar