Neuroscience research
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Neuroscience research · Sep 2010
Identification of male-biased gene: parvalbumin in song control nuclei of the Bengalese finch.
Sex differences in song nuclei are evident across songbirds. To explore candidate genes involving in the sexual dimorphism of song nuclei, the present study used suppression subtraction hybridization to identify male-biased genes in the Bengalese finch (Lonchura striata). ⋯ The total number of PV mRNA or protein cells was significantly larger in males in the HVC, RA, and Area X for PD45 and adult. Considering that calcium-binding proteins have reported effects on the maturation of some brain areas, and on the sexual differentiation of mammalian brain areas by affecting cell survival rates, our study suggests that PV may be involved in the functional maturation of neurons in song nuclei or the sexual differentiation of song system.
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Neuroscience research · May 2010
Blockade of dorsal hippocampal dopamine receptors inhibits state-dependent learning induced by cannabinoid receptor agonist in mice.
To clarify the interaction between cannabinnoid CB1 receptors and the dopaminergic system in memory processes, the effects of dopamine receptor agents on the state-dependent learning induced by the non-selective CB1/CB2 receptor agonist, WIN55,212-2 have been investigated in mice. Animals implanted with unilateral cannula at the CA1 region of the dorsal hippocampus and microinjected with WIN55,212-2 and/or dopaminergic agents, were tested using a single-trial step-down passive avoidance task. Intra-CA1 microinjections of WIN55,212-2 (0.1-1 microg/mouse) immediately after training, decreased the step-down latency, indicating an amnesic effect of the drug. ⋯ Pre-test microinjection of the same doses of SCH23390 or sulpiride had no effect on WIN55,212-2-induced amnesia. Moreover, single injection of SCH23390 (0.2 and 0.3 microg/mouse) or sulpiride (0.125 microg/mouse) decreased memory retrieval. The results suggest that the dorsal hippocampal dopaminergic system participates in the modulation of WIN55,212-2-induced state-dependent learning.
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Neuroscience research · Feb 2010
Comparative StudyComparison of milnacipran, duloxetine and pregabalin in the formalin pain test and in a model of stress-induced ultrasonic vocalizations in rats.
Milnacipran and duloxetine, serotonin/noradrenalin reuptake inhibitors, and pregabalin, a alpha(2)-delta(1) Ca(2+) channel blocker, are efficacious against fibromyalgia, a condition characterized by diffuse chronic pain and associated with stress. We compared these compounds (i.p. route), in rat models of acute/inflammatory pain (2.5% intraplantar formalin) and stress-induced ultrasonic vocalization (USV: 22kHz calls following presentation of a conditioned stimulus previously associated with foot-shocks). In the formalin test, milnacipran dose-dependently attenuated paw elevation and licking (minimal effective dose, MED: 2.5mg/kg for licking/late phase). ⋯ Milnacipran, duloxetine and pregabalin possess analgesic activity in the formalin test on paw licking/late phase (corresponding to inflammatory pain with a central sensitization component). In the stress-induced USV model, milnacipran was the most potent and efficacious compound. To summarize, reduction of formalin-induced paw licking/late phase might constitute a useful indicator of potential activity against inflammatory/centrally sensitized pain, as might be expressed in fibromyalgia.
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Neuroscience research · Feb 2010
Types and density of calretinin-containing retinal ganglion cells in mouse.
Calcium-binding proteins are present in a number of retinal cell types. Types and density of parvalbumin-immunoreactive (IR) retinal ganglion cells (RGCs) in the mouse retina were previously reported using a newly developed single-cell injection technique following immunocytochemistry [Kim, T. J., Jeon, C. ⋯ The present study showed that 86.59% (38,842/44,857) of RGCs contained calretinin. The density of calretinin-IR ganglion cell in the mouse retina was 2795cells/mm(2). The combined approach of cell morphology and the selective expression of a particular protein would provide valuable data for further knowledge on functional features of the RGCs.
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Neuroscience research · Dec 2009
Radiological and histological changes following cerebral venous sinus thrombosis in a rat model.
Cerebral venous sinus thrombosis (CVST) is an important cause of stroke in young especially after pregnancy. We induced CVST in rat by topical application of ferric chloride over the exposed superior sagittal sinus (SSS) and pathological changes were monitored on days 1, 2 and 7. Thrombus weight was estimated and H&E staining was performed for comparison with MRI data. ⋯ On histological evaluation, neuronal necrosis and cellular infiltration were observed in cortical region after thrombosis. The early decrease in ADC could be attributed to cytotoxic edema that precedes vasogenic edema indicated by normalization of ADC and a decreased T2 hyper intensity. In conclusion, ferric chloride induced CVST in the rat produces cytotoxic edema in early stage followed by vasogenic edema which is related to recanalization of the superior sagittal sinus.