So far, sigma-ligands have been investigated for several indications in human studies in functional diarrhea as a model of somatoform disorder (igmesine), depression (igmesine, opipramol), anxiety (opipramol and--in animal models--siramisine), schizophrenia (panamasine, SL 82.0715, rimcazole, DuP 734, BMY 14 802), and somatoform disorders (opipramol). Results for schizophrenia failed to be clear cut and so investigations have apparently stopped for the time being. The Sigma-1-selective igmesine (200 mg) showed good results in a phase-1-model of functional diarrhea and some promising results in depressed patients. However, further development has been stopped due to marketing reasons, which is also true for siramasine, a selective sigma-2-ligand with anxiolytic properties. Opipramol, which, apart from a sigma-1- and 2-receptor liability, also possesses histamine-H(1)-antagonistic properties in connection with lower affinities for D(2) and 5-HT(2A) showed broad efficacy in generalized anxiety disorder and somatoform disorders. The receptor profile of opipramol and the results of studies of the selective sigma site ligands siramisine and igmesine suggest that opipramol acts pharmacologically and clinically via sigma receptors.

2001-05-01·Brain Research4区 · 医学

Lack of effects by σ ligands on neuropeptide Y-induced G-protein activation in rat hippocampus and cerebellum

4区 · 医学

Article

作者: Linda Werling ; Weimin Hong

It has been suggested that neuropeptide Y (NPY) and sigma (sigma) receptor ligands may share a putative NPY/sigma receptor in rat brain. To study whether NPY and sigma receptor ligands have an inverse agonism at this putative NPY/sigma receptor, we measured their effects on G-protein activity in rat brain. Using [35S]GTPgammaS autoradiography, we found that NPY-induced G-protein activation exhibited a discrete distribution pattern in rat brain. G-protein activation in superficial cortical layers and hippocampal CA1-3 region was mainly attributed to Y1 and Y2 receptors, respectively. In the presence of 10 microM sigma-receptor agonist BD737 or 10 microM sigma-receptor antagonist haloperidol, the distribution and density of [35S]GTPgammaS binding stimulated by 10 nM NPY was not significantly altered. In rat cerebellar membranes, NPY stimulated high-affinity GTPase activity in a dose-related manner, with maximal effects of 29% increase over basal level seen at 500 nM. This NPY-elicited GTPase activity was not significantly affected by micromolar concentrations of the sigma-receptor antagonists Dup734 or haloperidol. Since no significant effects by sigma-receptor ligands on NPY-induced G-protein activation were observed, we did not see an inverse agonism of NPY and sigma-receptor ligands at the putative NPY/sigma receptor measured at the level of G-protein activation, suggesting that sigma receptors and NPY receptors do not represent a common population in rat hippocampus and cerebellum. It is also suggested that G-protein activation is not a convergent point for the signal transduction mechanisms of NPY receptors and sigma receptors.

2000-03-21·Psychopharmacology3区 · 医学

Z-IQNP: a potential radioligand for SPECT imaging of muscarinic acetylcholine receptors in Alzheimer's disease

3区 · 医学

Article

作者: K Nobuhara ; P O Schnell ; L Farde ; G Sedvall ; S Pauli ; C G Swahn ; J Hiltunen ; P Karlsson ; H Hall ; A Savonen ; K A Bergström ; S A Larsson ; D W McPherson ; C Halldin

RATIONALEThe density of the M2 subtype of muscarinic acetylcholine receptors (mAChR) has been shown to be reduced in the brain of patients with Alzheimer's disease (AD). It is therefore of interest to develop a brain imaging method for diagnostic purposes. Z-(R,R)-1-azabicyclo[2.2.2]oct-3-yl alpha-hydroxy-alpha-(1-iodo1-propen-3-yl)-alpha-phenylacetat e (Z-IQNP) is a muscarinic antagonist with high affinity for the M2 subtype.OBJECTIVEThe pharmacological characteristics and topographic distribution of radiolabelled Z-IQNP as a radioligand for the M2 mAChR subtype were examined in vitro and in vivo.METHODSZ-IQNP was labelled with 1251 and 123I. Autoradiography was performed on whole-hemisphere cryosections from human post mortem brains. SPECT was performed in a cynomolgus monkey.RESULTSAutoradiography showed binding of [125I]Z-IQNP in all brain regions, which was inhibited by the non-selective muscarinic antagonist scopolamine. The addition of BIBN 99, a compound with high affinity for the M2 subtype, inhibited [125I]Z-IQNP binding particularly in the cerebellum, which has a high density of the M2 subtype. SPECT demonstrated high uptake of [123I]Z-IQNP in all brain regions. The binding was markedly reduced in all brain regions after pretreatment with the non-selective muscarinic antagonist dexetimide and also the M1 antagonist biperiden. Dexetimide markedly inhibited [123I]Z-IQNP binding in the cerebellum, which is consistent with a high density of M2-receptors in this region. The sigma receptor binding compound DuP 734 had no effect on Z-IQNP binding either in vitro or in vivo.CONCLUSIONSThis study indicates that radiolabelled Z-IQNP has high specificity for mAChR with higher affinity for the M2 than the M1 subtype and negligible affinity for sigma recognition sites both in vitro and in vivo. [123I]Z-IQNP should be useful for future SPECT studies in AD for examination of the density of M2 receptors particularly in the cerebellum.

100 项与 DUP-734 相关的药物交易

登录后查看更多信息