Neuroscience letters
-
Neuroscience letters · Oct 2016
Localization of organic cation transporter 2 (OCT2) in monoaminergic and cholinergic axon terminals of the mouse brain.
Organic cation transporters (OCTs) are low-affinity, high-capacity carriers that mediate sodium-independent transport for biogenic cations, including catecholamine, serotonin, histamine, and choline/acetylcholine. Among them, OCT2 is expressed in neurons of the central nervous system. Although previous studies show OCT2 expression in several populations of cholinergic and monoaminergic neurons, the regional distribution of OCT2 in the brain remains largely unknown. ⋯ Interestingly, OCT2 appeared as punctate, bouton-like labeling in cholinergic, dopaminergic, and serotonergic axon terminals that were co-labeled with presynaptic neurochemical markers. We also co-labeled OCT2 and an anterograde tract-tracer injected into the locus coeruleus, demonstrating that OCT2 was localized to presumptive noradrenergic terminals in the forebrain. Together, our results demonstrated that the polyspecific cation transporter OCT2 is distributed in cholinergic and monoaminergic terminals in various forebrain regions, suggesting that OCT2 could play a role in regulating presynaptic reuptake and recycling of choline and monoamines.
-
Neuroscience letters · Oct 2016
Transcranial flavoprotein-autofluorescence imaging of sound-evoked responses in the mouse auditory cortex under three types of anesthesia.
The effects of anesthesia on the functional auditory characteristics of cortical neurons, such as spatial and temporal response properties, vary between an anesthetized and an awake subject. However, studies have shown that an appropriate anesthetic method that approaches the awake condition is still useful because of its greater stability and controllability. The present study compared neural response properties from two core fields of the mouse auditory cortex under three anesthetic conditions: urethane; ketamine and xylazine hydrochloride (KX) mixture; and a combination of medetomidine, midazolam, and butorphanol (MMB). ⋯ Results showed larger response peak intensity, latency, and duration in the core subfields under urethane compared with KX and MMB, with no significant differences between KX and MMB. Conversely, under KX anesthesia the activated areas showed characteristic response properties in a subfield-dependent manner. These results demonstrated the varied effects of anesthesia on response properties in the core subfields of the auditory cortex.
-
Neuroscience letters · Oct 2016
Suppressed GABAergic signaling in the zona incerta causes neuropathic pain in a thoracic hemisection spinal cord injury rat model.
Suppression of the gamma-aminobutyric acid (GABA)ergic activity of the zona incerta (ZI) reportedly plays a role in neuropathic pain after spinal cord injury (SCI). A reduction in GABAergic signaling in the ZI of a thoracic hemisection-SCI rat model has been suggested, but not clearly demonstrated. Accordingly, our objective was to investigate whether GABAergic signals influence SCI-induced neuropathic pain. ⋯ These data provide evidence that neuropathic pain after SCI is caused by decreased GABAergic signaling in the ZI. Furthermore, our data demonstrate that infusion of a GABAergic drug into the ZI could restore its inhibitory action and improve neuropathic pain behaviors.
-
Neuroscience letters · Oct 2016
Differential patterns of regional cerebral hypometabolism according to the level of cerebral amyloid deposition in patients with amnestic mild cognitive impairment.
Although amnestic mild cognitive impairment (aMCI) with high cerebral deposition of amyloid-beta proteins (Aβ) could be classified as a prodromal state of Alzheimer's disease (AD) dementia, aMCI with the absence of or very little cerebral Aβ deposition is likely related to other pathophysiological processes. Thus, the present study aimed to investigate the differential patterns of regional cerebral glucose metabolism (rCMglu) according to the level of Aβ burden in the brains of patients with aMCI. This study included 25 patients with aMCI and 33 cognitively normal (CN) elderly individuals who underwent a comprehensive clinical examination, (11)C-labelled Pittsburgh Compound B (PiB) positron emission tomography (PET) scans, and (18)F-fluorodeoxyglucose (FDG) PET scans. ⋯ Compared with the CN group, rCMglu was decreased in the bilateral medial temporal regions of the aMCI- subgroup and in the medial temporal cortices as well as the right precuneus of the aMCI+ subgroup. Additionally, rCMglu was lower in the right precuneus of the aMCI+ subgroup compared with the aMCI- subgroup. The present findings indicate that, even though both aMCI subgroups were phenomenologically very similar, the patients with aMCI- exhibited a markedly different regional pattern of functional neurodegeneration compared with the aMCI+ patients.
-
Neuroscience letters · Oct 2016
Association of DYRK1A polymorphisms with sporadic Parkinson's disease in Chinese Han population.
α-Synuclein plays important roles in the development of Parkinson's disease (PD) pathologies. The dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) has a wide range of phosphorylation targets including α-synuclein. Posphorylated α-synuclein is more neurotoxic to dopamine (DA) neurons, but little is known about the genetic variation of DYRK1A in patients with PD. ⋯ Results revealed TT genotype in SNP rs8126696 denoted a significant difference between PD patients and controls (OR=1.710, 95% CI=1.116-2.619, P=0.014), and the frequency of rs8126696 TT genotype was significantly higher in male PD patients than male controls (OR=2.012, 95%CI: 1.125-3.599, p=0.018). The genotypes in rs2835740 and rs1137600 showed no significant difference between PD patients and controls. These results suggest that TT genotype derived from SNP rs8126696 of DYRK1A gene is a possible risk factor for sporadic PD, especially for males in this Chinese Han population.