The Mesolimbic Dopamine Reward Circuit in Depression

All antidepressants in use today act via the monoamine neurotransmitters However, only ∼50% of individuals with depression show full remission Berton and Nestler review recent development of alternative, non-monoamine-based antidepressants, highlighting the obstacles and some of the most promising strategies All available antidepressant medications are based on serendipitous discoveries of the clinical efficacy of two classes of antidepressants more than 50 years ago These tricyclic and monoamine oxidase inhibitor antidepressants were subsequently found to promote serotonin or noradrenaline function in the brain Newer agents are more specific but have the same core mechanisms of action in promoting these monoamine neurotransmitters This is unfortunate, because only ∼50% of individuals with depression show full remission in response to these mechanisms This review summarizes the obstacles that have hindered the development of non-monoamine-based antidepressants, and provides a progress report on some of the most promising current strategies

New approaches to antidepressant drug discovery: beyond monoamines

| All available antidepressant medications are based on serendipitous discoveries of the clinical efficacy of two classes of antidepressants more than 50 years ago. These tricyclic and monoamine oxidase inhibitor antidepressants were subsequently found to promote serotonin or noradrenaline function in the brain. Newer agents are more specific but have the same core mechanisms of action in promoting these monoamine neurotransmitters. This is unfortunate, because only ∼50% of individuals with depression show full remission in response to these mechanisms. This review summarizes the obstacles that have hindered the development of non-monoamine-based antidepressants, and provides a progress report on some of the most promising current strategies.

New approaches to antidepressant drug discovery : beyond monoamines

The many faces of CREB

Assessing substrates underlying the behavioral effects of antidepressants using the modified rat forced swimming test.

We showed previously that cAMP response element-binding protein (CREB) within the nucleus accumbens (NAc) of rats regulates immobility in the forced swim test (FST), an assay used to study depression. Because CREB regulates expression of dynorphin (which acts at kappa-opioid receptors) in NAc neurons, these findings raised the possibility that kappa-receptors mediate immobility behaviors in the FST. Here, we report that i.c.v. administration of the kappa-antagonist nor-binaltorphimine dose dependently decreased immobility in the FST, suggesting that it has antidepressant-like effects. Implicating a specific effect at kappa-receptors, similar antidepressant-like effects were seen after treatment with either of two novel, structurally dissimilar kappa-antagonists: 5'-guanidinonaltrindole, which was effective after i.c.v. but not systemic treatment, and 5'-acetamidinoethylnaltrindole (ANTI), which was potent and effective after systemic treatment. The behavioral effects of the kappa-antagonists resembled those of tricyclic antidepressants (desipramine) and selective serotonin reuptake inhibitors (fluoxetine and citalopram). Conversely, systemic administration of the kappa-agonist [5alpha,7alpha,8beta]-N-methyl-N-[7-[1-pyrrolidinyl]-1-oxaspiro[4.5]dec8-yl]-benzenacetamide (U-69593) dose dependently increased immobility in the FST, consistent with prodepressant-like effects. The effects of the kappa-ligands in the FST were not correlated with nonspecific effects on locomotor activity. Furthermore, the most potent and effective kappa-antagonist (ANTI) did not affect the rewarding impact of lateral hypothalamic brain stimulation at a dose with strong antidepressant-like effects. These findings are consistent with the hypothesis that CREB-mediated induction of dynorphin in the NAc "triggers" immobility behavior in the FST. Furthermore, they raise the possibility that kappa-antagonists may have efficacy as antidepressants, but lack stimulant or reward-related effects.

https://jpet.aspetjournals.org/content/jpet/early/2003/01/21/jpet.102.046433.full.pdf

Antidepressant-Like Effects of κ-Opioid Receptor Antagonists in the Forced Swim Test in Rats

The estrogen-related receptor alpha (ERRalpha) is an orphan receptor belonging to the nuclear receptor superfamily. The physiological role of ERRalpha has yet to be established primarily because of lack of a natural ligand. Herein, we describe the discovery of the first potent and selective inverse agonist of ERRalpha. Through in vitro and in vivo studies, these ligands will elucidate the endocrine signaling pathways mediated by ERRalpha including association with human disease states.

Identification of a selective inverse agonist for the orphan nuclear receptor estrogen-related receptor alpha.

The indole moiety in the delta-opioid antagonist, naltrindole (2, NTI), was employed as a scaffold to hold an “address” for interaction with the kappa-opioid receptor. The attachment of the address to the 5‘-position of the indole moiety was based on superposition of NTI upon the kappa antagonist, norbinaltorphimine (1, norBNI). A variety of cationic groups were employed as a kappa address in an effort to investigate its interaction with the anionic address subsite, Glu297, on the kappa receptor. Some of the groups that were employed for this purpose were amines, amidines, guanidines, and quaternary ammonium. Members of the series were found to have a varying degree of kappa antagonist potency and kappa selectivity when tested in smooth muscle preparations. The 5‘-guanidine derivative 12a (GNTI) was the most potent member of the series and had the highest kappa selectivity ratio. GNTI was 2 times more potent and 6−10-fold more selective than norBNI (1). In general, the order of potency in the series was: ...

Potent and Selective Indolomorphinan Antagonists of the Kappa-Opioid Receptor

Compounds of formula (I) are provided as well as compositions and methods of using compounds of formula (I) for modulating the activity of the estrogen-related receptors and for the treatment, prevention, or amelioration of one or more symptoms of disease or disorder related to the activity of the estrogen-related receptor. Considering the wide range of activity of the nuclear hormone receptor ERRα, the compounds described herein which are capable of modulating ERRα activity, are useful for treating a range of disease states including cancer, diabetes, obesity, hyperlipidermia, arthritis, atherosclerosis, osteoporosis, anxiety, depression, Parkinson’s disease and Alzheimer’s disease. Formula (I). The substituents are defined in the claims.

3-phenyl-n- ((1, 3, 4) thiadiazol-2-yl) -acrylamide derivatives and related compounds as modulators of estrogen-related receptors for the treatment of e.g. cancer, rheumatoid arthritis or neurological disorders

William C. Stevens

Papers

Antidepressant-Like Effects of κ-Opioid Receptor Antagonists in the Forced Swim Test in Rats

Identification of a selective inverse agonist for the orphan nuclear receptor estrogen-related receptor alpha.

Potent and Selective Indolomorphinan Antagonists of the Kappa-Opioid Receptor

3-phenyl-n- ((1, 3, 4) thiadiazol-2-yl) -acrylamide derivatives and related compounds as modulators of estrogen-related receptors for the treatment of e.g. cancer, rheumatoid arthritis or neurological disorders

Pyrrolderivate als pharmazeutische wirkstoffe