Brain research bulletin
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Brain research bulletin · Apr 2009
Cornel iridoid glycoside promotes neurogenesis and angiogenesis and improves neurological function after focal cerebral ischemia in rats.
The aim of this study was to investigate the effects of cornel iridoid glycoside (CIG), an ingredient extracted from a traditional Chinese herb Cornus officinalis, on neurological function and neurogenesis after ischemic stroke. CIG was intragastrically administered to rats in doses of 20, 60 and 180 mg/kg/day, starting 3 h after the onset of middle cerebral artery occlusion (MCAO). The behavioral test was performed by using the modified neurological severity score (mNSS). ⋯ The number of newly mature neurons and blood vessels in striatum, as indicated by BrdU/NeuN and vWF immunoreactivity, respectively, was also increased in CIG-treated rats 28 days after stroke. CIG treatment obviously enhanced the mRNA expression of VEGF and its receptor Flk-1 and the protein expression of VEGF 7 and 28 days after ischemia. The results indicated that CIG promoted neurogenesis and angiogenesis and improved neurological function after ischemia in rats, and the mechanism might be related to CIG's increasing VEGF and Flk-1 in the brain.
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Brain research bulletin · Apr 2009
Racemic intrathecal mirtazapine but not its enantiomers acts anti-neuropathic after chronic constriction injury in rats.
The unique noradrenergic and specific serotonergic antidepressant mirtazapine acts antinociceptive. It is optically active and currently marketed as racemate. In an animal model of acute pain it has been shown that the enantiomers exhibit differential effects: the R(-)-enantiomer showed anti-, the S(+)-enantiomer pronociceptive properties while the racemate acted antinociceptive at low doses and profoundly pronociceptive after high-dose application. ⋯ Our findings suggest that the synergism of both enantiomers is required to evoke a significant analgesic effect for the treatment of neuropathic pain. Our study gained no evidence for the use of either R(-) nor S(+)-mirtazapine alone. Due to the unique characteristics of (+/-)-mirtazapine and its proven efficacy in acute pain our results suggest that racemic mirtazapine may be a particularly useful antidepressant in the adjunctive treatment of chronic neuropathic pain states and could provide additional benefit to current therapeutic options.
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Brain research bulletin · Apr 2009
Short-term habituation of eye-movement responses induced by galvanic vestibular stimulation (GVS) in the alert guinea pig.
In a recent study, we showed that primary afferent neurons innervating all vestibular end organs were sensitive to galvanic vestibular stimulation (GVS) in guinea pigs. In order to determine the three-dimensional character of eye movements induced by GVS, changes in eye position were recorded using digital video oculography during delivery of bilateral GVS ranging in intensity between 20 and 80 microA. Pulses were delivered in repetitive trains in order to also ascertain the involvement of vestibular habituation. ⋯ Nystagmus was found to habituate rapidly over successive presentations of GVS, whereas the tonic deviation of the eye remained consistent without any detectable habituation. The direction of eye movements induced by GVS was similar to that observed in humans during trans-mastoidal GVS, and the threshold differences between tonic and phasic components for GVS were also similar to previous human GVS studies. The observed habituation appears to be more specific to the phasic VOR component in quadrupedal animals such as guinea pigs, and this may reflect a considerable emphasis placed on otolithic stimulation in these animals during complex locomotor activities.
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Brain research bulletin · Mar 2009
Additive anti-hyperalgesia of electroacupuncture and intrathecal antisense oligodeoxynucleotide to interleukin-1 receptor type I on carrageenan-induced inflammatory pain in rats.
Accumulating evidence shows that spinal interleukin-1beta (IL-1beta) plays a critical role in inflammatory pain. Electroacupuncture (EA) can effectively attenuate inflammatory hyperalgesia both in clinical practices and experimental studies. However, little is known about the relationship between spinal IL-1beta and EA analgesia. ⋯ Down-regulation of IL-1RI expression by repeated intrathecal antisense ODN (50 microg/10 microl) significantly increased the mean PWL up to 5.75+/-0.15 s in 180-300 min post-carrageenan injection. Additionally, when the combination of EA with antisense ODN was used, thermal hyperalgesia was further alleviated than EA or antisense ODN alone, with a maximum PWL of 7.66+/-0.50 s at 30 min post the beginning of EA treatment. The results suggested an involvement of the spinal IL-1beta/IL-1RI system in EA-induced anti-hyperalgesia in inflammatory pain.
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Brain research bulletin · Mar 2009
The detection and measurement of locomotor deficits in a transgenic mouse model of Huntington's disease are task- and protocol-dependent: influence of non-motor factors on locomotor function.
Locomotor performance of transgenic R6/2 mice carrying the Huntington's disease (HD) mutation was assessed using four different tasks, fixed speed rotarod, accelerating rotarod, Digigait and footprint test. The tasks were compared directly in age- and CAG repeat-matched R6/2 mice. Accelerating rotarod was more sensitive than fixed speed rotarod for detecting early motor deficits in R6/2 mice. ⋯ The fact that the sensitivity for detecting motor deficits depended strongly on the individual task, and on the protocol used, suggests that non-motor factors were differentially engaged in the different paradigms. We thus recommend that more than one task should be used for detecting and tracking different aspects of motor decay in animal models of HD. Since deficits in non-motor factors such as executive function and motivation may differentially influence motor outcome in each task, our results call for a more thorough investigation of the importance of higher level control of locomotion in animal models of HD.