Physiology & behavior
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Physiology & behavior · Dec 2010
Treadmill exercise inhibits traumatic brain injury-induced hippocampal apoptosis.
Traumatic brain injury (TBI) occurs when an outside force impacts the brain. The main problem associated with TBI is neuronal cell death of the brain, and the outcome of TBI ranges from complete recovery to permanent disability, and sometimes death. Physical exercise is known to ameliorate neurologic impairment induced by various brain insults. ⋯ Treadmill exercise alleviated short-term memory impairment, and decreased DNA fragmentation and caspase-3 expression in the hippocampus. In addition, treadmill exercise remarkably suppressed expression of Bax protein and slightly increased expression of Bcl-2 protein in TBI-induced rats. The present study showed that treadmill exercise might overcome TBI-induced apoptotic neuronal cell death, thus facilitating recovery following TBI.
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Physiology & behavior · Dec 2010
Progesterone rapidly recruits female-typical opioid-induced hyperalgesic mechanisms.
Continuous morphine treatment can paradoxically increase nociception (i.e. hyperalgesia) in male and female mice, but sex differences have been reported. Here, we studied progesterone modulation of these differences by assessing nociception on the tail-withdrawal test in male and female mice rendered hyperalgesic during continuous infusion of two different morphine doses (1.6 and 40.0mg/kg/24h). Although the lower morphine infusion dose increased nociception in both sexes by infusion Day 4, this hyperalgesia dissipated by Day 6 in males and ovariectomized females, but not gonadally intact females. ⋯ However, the NMDA receptor antagonist MK-801 (0.05mg/kg) reversed hyperalgesia in males and ovariectomized females but not gonadally intact females on infusion Day 6. Subcutaneous progesterone (0.0016mg/kg) injection inhibited this reversal in male and ovariectomized female mice but had no effect on nociception in saline-infused mice of either sex. These data confirm our previous findings that male and female mice utilize distinct hyperalgesic mechanisms, and show for the first time that a single progesterone bolus dose can recruit female-typical hyperalgesia in ovariectomized females and males.