Brain research bulletin
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Brain research bulletin · Sep 2017
Influence of social interaction on nociceptive-induced changes in locomotor activity in a mouse model of acute inflammatory pain: Use of novel thermal assays.
Most acute and chronic animal models of pain rely heavily on reflexive assays for evaluating levels of nociception, which involves removing the animal from its normal social environment. Here, we examine and characterize the influence of social interactions on inflammatory pain-evoked changes in movement in two different mouse strains. To produce inflammatory nociception, we injected CFA bilaterally into the hind paws of Balb/c and C3H mice and then recorded exploratory locomotor activity using an automated detector system to first evaluate the effects of social behavior on nociception. ⋯ Carprofen administration completely blocked this CFA-induced hyperlocomotor activity. Both heat and cold induced a significant increase in locomotor activity in paired mice injected with CFA, while having no effect on activity in control mice injected with saline. The results presented here indicate that social interactions greatly influence inflammatory pain-induced changes in locomotor activity and indicate that the use of movement-based assays to evaluate nociception in paired mice may provide an alternative and more sensitive method to quantify nociception and characterize novel analgesic effects over time in the context of social interactions in rodent models of pain.
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Brain research bulletin · Sep 2017
The effect of monascin on hematoma clearance and edema after intracerebral hemorrhage in rats.
Intracerebral hemorrhage (ICH) is a particularly devastating form of stroke with high mortality and morbidity. Hematomas are the primary cause of neurologic deficits associated with ICH. The products of hematoma are recognized as neurotoxins and the main contributors to edema formation and tissue damage after ICH. Finding a means to efficiently promote absorption of hematoma is a novel clinical challenge for ICH. Peroxisome proliferator-activated receptor gamma (PPARγ) and nuclear factor erythroid 2-related factor 2 (Nrf2), had been shown that, can take potential roles in the endogenous hematoma clearance. However, monascin, a novel natural Nrf2 activator with PPARγ agonist, has not been reported to play a role in ICH. This study was designed to evaluate the effect of monascin on neurological deficits, hematoma clearance and edema extinction in a model of ICH in rats. ⋯ Our study demonstrated that the high dosage of monascin played a neuroprotective role in ICH through reducing BBB permeability, edema and hematoma volume.
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Brain research bulletin · May 2017
L-carnitine prevents memory impairment induced by chronic REM-sleep deprivation.
Sleep deprivation (SD) negatively impacts memory, which was related to oxidative stress induced damage. L-carnitine is a naturally occurring compound, synthesized endogenously in mammalian species and known to possess antioxidant properties. In this study, the effect of L-carnitine on learning and memory impairment induced by rapid eye movement sleep (REM-sleep) deprivation was investigated. ⋯ Furthermore, L-carnitine normalized chronic REM-sleep deprivation induced reduction in the hippocampus ratio of GSH/GSSG, activity of catalase, GPx, and SOD. No change was observed in TBARS among tested groups (P>0.05). In conclusion, chronic REM-sleep deprivation induced memory impairment, and treatment with L-carnitine prevented this impairment through normalizing antioxidant mechanisms in the hippocampus.
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Brain research bulletin · May 2017
Neurogenic bladder dysfunction does not correlate with astrocyte and microglia activation produced by graded force in a contusion-induced spinal cord injury.
Rodent models for the study of neurogenic bladder dysfunction after spinal cord injury (SCI) are difficult to standardize, particularly when evaluating the specific contribution of the SCI to end-organ function. The purpose of this study was to evaluate the degree of bladder dysfunction associated with a highly reproducible, contusion-induced SCI in female rats. An infinite horizon impactor was used to create a contusion SCI with a magnitude of either 100 or 150 kDyne at the T8/T9 thoracic region of female Sprague-Dawley rats. ⋯ After performing the cystometric studies substantial differences were found in both SCI groups when compared to intact animals, specifically a high frequency of non-voiding contractions, different durations for intraluminal pressure-high frequency oscillations, intercontractile intervals, impaired micturition volumes, and estimated voiding efficiency. These results suggest that a contusion SCI can increase microglia and astrocyte activation without a strong association with bladder dysfunction. The present study will be important for precise considerations about correlating the intensity of an SCI with impairment outcomes at both locomotor or organ function levels.
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Brain research bulletin · Apr 2017
NMDA receptor adjusted co-administration of ecstasy and cannabinoid receptor-1 agonist in the amygdala via stimulation of BDNF/Trk-B/CREB pathway in adult male rats.
Consumption of cannabinoid receptor-1 (CB-1) agonist such as cannabis is widely taken in 3,4- methylenedioxymethamphetamine (MDMA) or ecstasy users; it has been hypothesized that co-consumption of CB-1 agonist might protect neurons against MDMA toxicity. N-methyl-d-aspartate (NMDA) receptors regulate neuronal plasticity and firing rate in the brain through Tyrosine-kinase B (Trk-B) activation. The molecular and electrophysiological association among NMDA and MDMA/Arachidonylcyclopropylamide (ACPA, a selective CB-1 receptor agonist) co-consumption was not well-known. ⋯ Interestingly, injection of ACPA+MDMA enhanced BDNF, Trk-B and CREB phosphorylation compared with MDMA groups. D-AP5, ACPA and MDMA co-injection decreased BDNF, Trk-B and CREB phosphorylation levels compared with ACPA+MDMA in the amygdala (P<0.01). Probably, NMDA receptors are involved in the protective role of acute MDMA+ACPA co-injection via BDNF/Trk-B/CREB pathways.