[Design, synthesis and bioactivity of aryl piperazine benzo[b][1,4]oxazine derivatives].

Compounds with serotonin reuptake inhibition/5-HT(1A) dual activity were used to build 3D pharmacophore model as a training molecules by Discover Studio. Based on the model, 8 novel aryl piperazine benzo[b][1,4] oxazine derivatives were designed and synthesized, and their structures were confirmed by 1H NMR and HR-MS. Biological evaluation illustrated that compounds VI(1) and VI(7) showed potent functional activities at both 5-HT transporter and 5-HT(1A) receptor, which can be used as lead compounds to guide future research of design and synthesis of potent novel compounds.

[Design and synthesis of nitrogen-containing benzoheterocyclic derivatives and their antipsychotic activities].

A series of nitrogen-containing benzoheterocyclic derivatives were synthesized and tested for their antipsychotic activities. Their structures were confirmed by 1H NMR and HR-MS. Preliminary in vitro pharmacological trials showed that most of the target compounds have high affinity with D2 and 5-HT(2A) receptors. Among the tested compounds, 20 exhibited the highest affinity and D2 partial agonist activity. In vivo studies showed 20 has potent antipsychotic activities on apomorphine mice model, which is a chance to find a better precursor of D2 partial agonist for further optimization.

L-stepholidine reduced L-DOPA-induced dyskinesia in 6-OHDA-lesioned rat model of Parkinson's disease.

L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID) remains a challenge in Parkinson's disease (PD) drug therapy. In the present study, we examined the effect of L-stepholidine (L-SPD), a known dual dopamine receptor agent, on LID in 6-hydroxydopamine (6-OHDA)-lesioned PD rat model. Daily administration of L-DOPA to PD rats for 22 days induced steady expression of LID, co-administration of L-SPD with L-DOPA significantly ameliorated LID without compromising the therapeutic potency of L-DOPA, indicating that L-SPD attenuated LID development. L-SPD alone elicited stable contralateral rotational behavior without inducing significant dyskinesia. Acute administration of L-SPD to rats with established LID produced significant relief of dyskinesia; this effect was mimicked by D(2) receptor antagonist haloperidol, but blunted by 5-HT(1A) receptor antagonist WAY100635. Furthermore, the mRNA level of 5-HT(1A) decreased significantly on 6-OHDA-lesioned striata, whereas chronic L-SPD treatment restored 5-HT(1A) receptor mRNA level on the lesioned striata. The present data demonstrated that L-SPD elicited antidyskinesia effects via both dopamine (D(2) receptor antagonistic activity) and nondopamine (5-HT(1A) agonistic activity) mechanisms.

Differential distributions and trafficking properties of dopamine D1 and D5 receptors in nerve cells.

OBJECTIVE: To explore the possible differential trafficking properties of the dopamine D1-like receptor subtypes, D1 receptor and D5 receptor. METHODS: To visualize distributions of dopamine D1-like receptor subtypes at subcellular level, the yellow and cyan variants of green fluorescent protein (GFP) were used to tag D1 and D5 receptors. After transfection with the tagged dopamine receptors, the neuroblastoma cells NG108-15 were treated with D1 agonist SKF38393 or acetylcholine (ACh). Then we observed the subcellular distributions of the tagged receptors under the confocal microscopy and tried to determine trafficking properties by comparing their distribution patterns before and after the drug treatment. RESULTS: In resting conditions, D1 receptors located in the plasma membrane of NG108-15 cells, while D5 receptors located in both plasma membrane and cytosol. With the pre-treatment of SKF38393, the subcellular distribution of D1 receptors was changed. The yellow particle-like fluorescence of tagged D1 receptors appeared in the cytosol, indicating that D1 receptors were internalized into cytosol from the cell surface. Same situation also occurred in ACh pre-treatment. In contrast, the subcellular distribution of D5 receptors was not changed after SKF38393 or ACh treatment, indicating that D5R was not translocated to cell surface. Interestingly, when D1 and D5 receptors were co-expressed in the same cell, both kept their distinct subcellular distribution patterns and the trafficking properties. CONCLUSION: Our present study reveals that in NG108-15 nerve cells, dopamine D1 and D5 receptors exhibit differential subcellular distribution patterns, and only D1 receptor has a marked trafficking response to the drug stimulation. We further discuss the potential role of the differential trafficking properties of D1-like receptors in complex modulation of DA signaling.

A novel therapeutic approach to 6-OHDA-induced Parkinson's disease in rats via supplementation of PTD-conjugated tyrosine hydroxylase.

The present study aimed to evaluate whether the protein transduction domain (PTD)-conjugated human tyrosine hydroxylase (TH) fusion protein was effective on the 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD) model rats. An expression vector pET-PTD-TH harbouring the PTD-TH gene was constructed and transformed to the Escherichia coli BL21 cells for expression. The expressed recombinant PTD-TH with a molecular weight of 61 kD was successfully transduced (1 microM) into the dopaminergic SH-sy5y human neuroblastoma cells in vitro and visualized by immunohistochemical assay. An in vivo experiment in rats showed that the iv administered PTD-TH protein (8 mg/kg) permeated across the blood-brain barrier, penetrated into the striatum and midbrain, and peaked at 5-8 h after the injection. The behavioral effects of PTD-TH on the apomorphine-induced rotations in the PD model rats 8 weeks after the 6-OHDA lesion showed that a single bolus of PTD-TH (8 mg/kg) iv injection caused a decrement of 60% of the contralateral turns on day 1 and 40% on days 5-17. The results imply that iv delivery of PTD-TH is therapeutically effective on the 6-OHDA-induced PD in rats, the PTD-mediated human TH treatment opening a promising therapeutic direction in treatment of PD.