Neurogenesis impairment with glial activation in the hippocampus-connected regions of intracerebroventricular streptozotocin-injected mice.

Adult neurogenesis in the hippocampus and subventricular zone (SVZ) is impaired by intracerebroventricular administration of streptozotocin (icv-STZ) to rodents. Although neural cells in the several brain regions which connect with the hippocampus or SVZ is thought to be involved in the adult neurogenesis, few studies have investigated morphological alterations of glial cells in these areas. The present study revealed that icv-STZ induces reduction of neural progenitor cells and a dramatic increase in reactive astrocytes and microglia especially in the hippocampus and various hippocampus-connected brain areas. In contrast, there was no significant neuronal damage excluding demyelination of the stria medullaris. The results indicate the hippocampal neurogenesis impairment of this model might be occurred by activated glial cells in the hippocampus, or hippocampus-connected regions.

A Unique Case of Sarcoid-associated Myelopathy Accompanied by Lung Cancer.

The differential diagnosis of myelopathy in patients with malignancies may be challenging, as a spinal biopsy is not always applicable. A 66-year-old woman who had shown transient double vision and nausea developed spasticity and impaired deep sensation in both feet. Magnetic resonance imaging showed abnormal gadolinium enhancement of the brainstem, spinal meninges, and nerve root. Cerebrospinal fluid (CSF) revealed mild pleocytosis and elevated protein and decreased glucose levels, although CSF cytology was normal. Lung carcinoma was simultaneously detected, and noncaseating granuloma was detected from the hilar and axillary lymph nodes, so she was diagnosed with sarcoid-associated myelopathy. Her symptoms were kept stable by intravenous methylprednisolone, oral prednisolone, and methotrexate. This is the first case of sarcoid-associated myelopathy accompanied by lung cancer, suggesting the importance of clinical course, repetitive CSF cytology, and a biopsy of the lymph nodes to distinguish sarcoid-associated myelopathy from meningeal metastasis in patients with malignancies.

Dopaminergic neuroprotective effects of rotigotine via 5-HT1A receptors: Possibly involvement of metallothionein expression in astrocytes.

Astrocytes exert neuroprotective effects through production of antioxidant molecules and neurotrophic factors. A recent study showed that stimulation of astrocyte serotonin 1A (5-HT1A) receptors promotes astrocyte proliferation and upregulation of the antioxidant molecules metallothionein (MT)-1,2, which protect dopaminergic neurons against oxidative stress. Rotigotine, an anti-parkinsonian drug, can bind to dopamine and 5-HT1A receptors. In this study, we examined neuroprotective effects of rotigotine in models of Parkinson's disease and involvement of astrocyte 5-HT1A receptors in neuroprotective effects of rotigotine against dopaminergic neurodegeneration. Rotigotine increased the number of astrocytes and MT-1,2 expression in cultured astrocytes. Pretreatment with conditioned media from rotigotine-treated astrocytes significantly inhibited 6-hydroxydopamine (6-OHDA)-induced dopaminergic neurotoxicity. These effects were completely blocked by a 5-HT1A antagonist or MT-1,2 specific antibody. Subcutaneous administration of rotigotine increased MT-1,2 expression in striatal astrocytes and prevented reduction of dopaminergic neurons in the substantia nigra of a 6-OHDA-lesioned mouse model of Parkinson's disease. These effects were blocked by co-administration with a 5-HT1A antagonist. These results suggest that rotigotine exerts neuroprotective effects through upregulation of MT expression in astrocytes by targeting 5-HT1A receptors. Our findings provide a possible therapeutic application of rotigotine to prevent dopaminergic neurodegeneration in Parkinson's disease.