Anxiety Disorders: Dautzenberg FM

Lavreysen H, Dautzenberg FM. · CNS Psychiatry, Janssen Pharmaceutica, a division of Johnson and Johnson Pharmaceutical Research and Development, 2340 Beerse, Belgium. · Curr Med Chem. · Pubmed #18336281 No free full text.

Abstract: Metabotropic glutamate (mGlu) receptors have received much attention, driven by a strong belief in the potential of these modulatory glutamate receptors as drug targets. So far, major drug discovery programs have largely focused on group I (mGlu1 and 5) and II (mGlu2 and 3) mGlu receptors, which have been implicated in neuropathological and various psychiatric disorders. The four group III representatives (mGlu4, mGlu6, mGlu7 and mGlu8) are less understood, mainly due to the paucity of specific compounds. Recent advances in the identification of selective or specific compounds, and the generation of transgenic animals have, however, revealed important insights into the potential role of group III receptors in the pathophysiology of neurological and mood disorders. Activation of the mGlu4 receptor seems to be beneficial for treating Parkinson-like symptoms and a potential role in the treatment of mood disorders is slowly growing. Similarly, genetic inactivation studies and usage of relatively selective agonists strongly support the involvement of the mGlu8 receptor for anxiety disorders. In contrast, controversial data have been obtained for the mGlu7 receptor. While mGlu7 receptor-deficient animals show an anxiolytic profile in several in vivo readouts, the first selective allosteric agonist AMN082 has also been reported to improve anxiety-like behaviour despite activating the stress axis. The least investigated receptor remains the mGlu6 receptor, which is mostly based on its predominant expression in the retina.

Hauger RL, Risbrough V, Brauns O, Dautzenberg FM. · San Diego VA Healthcare System, University of California San Diego, La Jolla, 929093-0603, USA. · CNS Neurol Disord Drug Targets. · Pubmed #16918397 links to  free full text

Abstract: Corticotropin-releasing factor (CRF) and the related urocortin peptides mediate behavioral, cognitive, autonomic, neuroendocrine and immunologic responses to aversive stimuli by activating CRF(1) or CRF(2) receptors in the central nervous system and anterior pituitary. Markers of hyperactive central CRF systems, including CRF hypersecretion and abnormal hypothalamic-pituitary-adrenal axis functioning, have been identified in subpopulations of patients with anxiety, stress and depressive disorders. Because CRF receptors are rapidly desensitized in the presence of high agonist concentrations, CRF hypersecretion alone may be insufficient to account for the enhanced CRF neurotransmission observed in these patients. Concomitant dysregulation of mechanisms stringently controlling magnitude and duration of CRF receptor signaling also may contribute to this phenomenon. While it is well established that the CRF(1) receptor mediates many anxiety- and depression-like behaviors as well as HPA axis stress responses, CRF(2) receptor functions are not well understood at present. One hypothesis holds that CRF(1) receptor activation initiates fear and anxiety-like responses, while CRF(2) receptor activation re-establishes homeostasis by counteracting the aversive effects of CRF(1) receptor signaling. An alternative hypothesis posits that CRF(1) and CRF(2) receptors contribute to opposite defensive modes, with CRF(1) receptors mediating active defensive responses triggered by escapable stressors, and CRF(2) receptors mediating anxiety- and depression-like responses induced by inescapable, uncontrollable stressors. CRF(1) receptor antagonists are being developed as novel treatments for affective and stress disorders. If it is confirmed that the CRF(2) receptor contributes importantly to anxiety and depression, the development of small molecule CRF(2) receptor antagonists would be therapeutically useful.

Dautzenberg FM, Hauger RL. · Therapeutic Applications, Axovan, Innovation Center, Gewerbestrasse 16, 4123, Allschwil, Switzerland. · Trends Pharmacol Sci. · Pubmed #11830263 No free full text.

Abstract: Abnormal signaling at corticotropin-releasing factor CRF1 and CRF2 receptors might contribute to the pathophysiology of stress-related disorders such as anxiety, depression and eating disorders, in addition to cardiac and inflammatory disorders. Recently, molecular characterization of CRF1 and CRF2 receptors and the cloning of novel ligands--urocortin, stresscopin-related peptide/urocortin II, and stresscopin/urocortin III--have revealed a far-reaching physiological importance for the family of CRF peptides. Although the physiological roles of the CRF2 receptor remain to be defined, the preclinical and clinical development of specific small-molecule antagonists of the CRF1 receptor opens new avenues for the treatment of psychiatric and neurological disorders.

Ahnaou A, Dautzenberg FM, Geys H, Imogai H, Gibelin A, Moechars D, Steckler T, Drinkenburg WH. · Dept. Neuroscience, A Division of Janssen Pharmaceutica NV, Johnson & Johnson Pharmaceutical Research and Development, RED Europe, Beerse, Belgium. · Eur J Pharmacol. · Pubmed #19046965 No free full text.

Abstract: Compiling pharmacological evidence implicates metabotropic glutamate mGlu(2) receptors in the regulation of emotional states and suggests positive modulators as a novel therapeutic approach of Anxiety/Depression and Schizophrenia. Here, we investigated subcutaneous effects of the metabotropic glutamate mGlu(2/3) agonist (LY354740) on sleep-wake architecture in rat. To confirm the specific effects on rapid eye movement (REM) sleep were mediated via metabotropic glutamate mGlu(2) receptors, we characterized the sleep-wake cycles in metabotropic glutamate mGlu(2) receptor deficient mice (mGlu(2)R(-/-)) and their arousal response to LY354740. We furthermore examined effects on sleep behavior in rats of the positive allosteric modulator, biphenyl-indanone A (BINA) alone and in combination with LY354740 at sub-effective doses. LY354740 (1, 3 and 10 mg/kg) dose-dependently suppressed REM sleep and prolonged its onset latency. Metabotropic glutamate mGlu(2)R(-/-) and their wild type (WT) littermates exhibited similar spontaneous sleep-wake phenotype, while LY354740 (10 mg/kg) significantly affected REM sleep variables in WT but not in the mutant. In rats, BINA (1, 3, 10, 20, 40 mg/kg) dose-dependently suppressed REM sleep, lengthened its onset latency and slightly enhanced passive waking. Additionally, combined treatment elicited a synergistic action on REM sleep variables. Our findings show common changes of REM sleep variables following modulation of metabotropic glutamate mGlu(2) receptor and support an active role of this receptor in the regulation of REM sleep. The synergistic action of BINA on LY354740's effects on sleep pattern implies that positive modulators would tune the endogenous glutamate tone suggesting potential benefit in the treatment of psychiatric disorders, in which REM sleep overdrive is manifested.

Oakley RH, Olivares-Reyes JA, Hudson CC, Flores-Vega F, Dautzenberg FM, Hauger RL. · Department of Psychiatry, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA. · Am J Physiol Regul Integr Comp Physiol. · Pubmed #17363685 No free full text.

Abstract: The primary goal was to test the hypothesis that agonist-induced corticotropin-releasing factor type 1 (CRF(1)) receptor phosphorylation is required for beta-arrestins to translocate from cytosol to the cell membrane. We also sought to determine the relative importance to beta-arrestin recruitment of motifs in the CRF(1) receptor carboxyl terminus and third intracellular loop. beta-Arrestin-2 translocated significantly more rapidly than beta-arrestin-1 to agonist-activated membrane CRF(1) receptors in multiple cell lines. Although CRF(1) receptors internalized with agonist treatment, neither arrestin isoform trafficked with the receptor inside the cell, indicating that CRF(1) receptor-arrestin complexes dissociate at or near the cell membrane. Both arrestin and clathrin-dependent mechanisms were involved in CRF(1) receptor internalization. To investigate molecular determinants mediating the robust beta-arrestin-2-CRF(1) receptor interaction, mutagenesis was performed to remove potential G protein-coupled receptor kinase phosphorylation sites. Truncating the CRF(1) receptor carboxyl terminus at serine-386 greatly reduced agonist-dependent phosphorylation but only partially impaired beta-arrestin-2 recruitment. Removal of a serine/threonine cluster in the third intracellular loop also significantly reduced CRF(1) receptor phosphorylation but did not alter beta-arrestin-2 recruitment. Phosphorylation was abolished in a CRF(1) receptor possessing both mutations. Surprisingly, this mutant still recruited beta-arrestin-2. These mutations did not alter membrane expression or cAMP signaling of CRF(1) receptors. Our data reveal the involvement of at least the following two distinct receptor regions in beta-arrestin-2 recruitment: 1) a carboxyl-terminal motif in which serine/threonine residues must be phosphorylated and 2) an intracellular loop motif configured by agonist-induced changes in CRF(1) receptor conformation. Deficient beta-arrestin-2-CRF(1) receptor interactions could contribute to the pathophysiology of affective disorders by inducing excessive CRF(1) receptor signaling.