28 research outputs found

    Presynaptic Actions of D2-Like Receptors in the Rat Cortico-Striato-Globus Pallidus Disynaptic Connection In Vitro

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    The cerebral cortex, the neostriatum (Str), and the external segment of the globus pallidus (GPe) form a cortico-Str-GPe disynaptic connection, which is one of the major connections in the basal ganglia circuitries and a target of dopamine modulation. The aim of this study was to examine the actions of D2-like dopamine receptors (D2LRs) in this connection using rat brain slice preparations. Electrical stimulation of the frontal cortex evoked disynaptic inhibitory postsynaptic currents (IPSCs) in cesium-filled GPe neurons voltage-clamped at 0 mV. The IPSCs evoked by threshold stimulation were small, <10 pA. Bath or local applications of the D2LR agonist quinpirole to Str decreased the amplitude of the cortical stimulation-induced IPSCs. Electrical stimulation of Str evoked monosynaptic IPSCs in GPe neurons. Local application of quinpirole to GPe decreased the Str stimulation-induced IPSCs. Bath application of quinpirole decreased the frequency of large miniature IPSCs (mIPSCs) that were considered to be evoked by local collateral axons of GPe neurons. These results suggested that activation of D2LRs decrease the gain of the cortico-Str-GPe disynaptic connection, with the decrease attributed to activation of D2LRs in Str and GPe, and that both Str-GPe and GPe-GPe GABAergic inhibitions are under the control of presynaptic D2LRs

    Clinical Features of Painful Ophthalmoplegia with a High-Intensity Ring Appearance around the Optic Nerve on MRI: A Case Series

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    Objective. Painful ophthalmoplegia includes nonspecific magnetic resonance imaging (MRI) manifestations and various clinical features including orbital pain and cranial nerve palsies. Treatment for painful ophthalmoplegia remains controversial. The aim of this report was to describe detailed clinical features, MRI findings, treatments, and prognosis of patients with painful ophthalmoplegia. Patients and Methods. We retrospectively investigated four cases of patients with painful ophthalmoplegia diagnosed using the International Classification of Headache Disorders, 3rd edition. Results. All patients experienced unilateral orbital pain and oculomotor nerve palsy with diplopia but no vision loss. One of the four patients was diagnosed with Tolosa–Hunt syndrome based on the appearance of a granulomatous inflammation of the cavernous sinus on MRI. No specific lesions were detected on brain MRI for the other three patients; therefore, their headaches were attributed to ischaemic ocular motor nerve palsy. In all patients, a high-intensity ring appearance around the ipsilateral optic nerve was observed on MRI. Steroid therapy was administered to these patients, and good prognoses were anticipated. Conclusion. These results indicate that prednisolone is a useful treatment for painful ophthalmoplegia that displays ipsilateral hyperintense ring lesions around the optic nerve on MRI, regardless of the presence of granulomatous inflammation of the cavernous sinus

    Expression of Sox genes in tooth development

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    Members of the Sox gene family play roles in many biological processes including organogenesis. We carried out comparative in situ hybridization analysis of seventeen sox genes (Sox1-14, 17, 18, 21) during murine odontogenesis from the epithelial thickening to the cytodifferentiation stages. Localized expression of five Sox genes (Sox6, 9, 13, 14 and 21) was observed in tooth bud epithelium. Sox13 showed restricted expression in the primary enamel knots. At the early bell stage, three Sox genes (Sox8, 11, 17 and 21) were expressed in pre-ameloblasts, whereas two others (Sox5 and 18) showed expression in odontoblasts. Sox genes thus showed a dynamic spatio-temporal expression during tooth development
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