Experimental neurology
-
Experimental neurology · Oct 2005
Comparative StudyHypoxia-inducible factor 1alpha and erythropoietin upregulation with deferoxamine salvage after neonatal stroke.
Treatment with deferoxamine (DFO) is protective against focal ischemia with global hypoxia when given as a preconditioning stimulus in neonatal rodents. DFO acts as an iron chelator and may stabilize HIF1alpha. Therefore, we hypothesized that DFO would protect against pure ischemia-reperfusion injury when given after the insult and that the protection would be associated with expression of hypoxia-inducible factor 1alpha (HIF1alpha) and downstream target genes such as erythropoietin (Epo). ⋯ In DFO-treated ischemic cortices, HIF1alpha expression peaked early, while Epo expression was seen in two phases and in different cell populations. Epo immunoreactivity colocalized with neuronal markers at 8 h but with astrocytic markers at 1 week. These results suggest that DFO is protective when administered after neonatal ischemic stroke and that this protection may be like that afforded by preconditioning through the upregulation of similar downstream pathways.
-
Experimental neurology · Oct 2005
Comparative StudyEffects of electroacupuncture on cold allodynia in a rat model of neuropathic pain: mediation by spinal adrenergic and serotonergic receptors.
The present study was performed to examine the effects of electroacupuncture (EA) on cold allodynia and its mechanisms related to the spinal adrenergic and serotonergic systems in a rat model of neuropathic pain. For the neuropathic surgery, the right superior caudal trunk was resected at the level between S1 and S2 spinal nerves innervating the tail. Two weeks after the nerve injury, EA stimulation (2 or 100 Hz) was delivered to Zusanli (ST36) for 30 min. ⋯ Although both 2 Hz and 100 Hz EA significantly relieved the cold allodynia signs, 2 Hz EA induced more robust effects than 100 Hz EA. In addition, intrathecal injection of yohimbine, NAN-190, and MDL-72222, but not prazosin and ketanserin, significantly blocked the relieving effects of 2 Hz EA on cold allodynia. These results suggest that low-frequency (2 Hz) EA is more suitable for the treatment of cold allodynia than high-frequency (100 Hz) EA, and spinal alpha2-adrenergic, 5-HT1A and 5-HT3, but not alpha1-adrenergic and 5-HT2A, receptors play important roles in mediating the relieving effects of 2 Hz EA on cold allodynia in neuropathic rats.
-
Experimental neurology · Oct 2005
Comparative StudyGender and environmental enrichment impact dopamine transporter expression after experimental traumatic brain injury.
Dopamine (DA) systems are implicated in cognitive deficits following traumatic brain injury (TBI). Rodent studies have demonstrated that both environmental enrichment (EE) and sex hormones can influence DA systems. The dopamine transporter (DAT) plays a crucial role in regulating DA transmission, and previous work shows that DAT is decreased after TBI in males. ⋯ There were decreases in DAT expression in three regions studied for injured males housed in the standard environment compared to sham males in the standard environment (P < 0.05 all comparisons), however, EE did not add significantly to post-injury DAT decreases in these regions. These results suggest that CCI causes larger relative decreases in DAT expression for males compared to females and that treatment with EE has larger effects on post-injury DAT expression for females than males. These findings may have some relevance to treatment paradigms using dopaminergic neurostimulants after TBI.