1
|
Mamach M, Kessler M, Bankstahl JP, Wilke F, Geworski L, Bengel FM, Kurt S, Berding G. Visualization of the auditory pathway in rats with 18F-FDG PET activation studies based on different auditory stimuli and reference conditions including cochlea ablation. PLoS One 2018; 13:e0205044. [PMID: 30278068 PMCID: PMC6168174 DOI: 10.1371/journal.pone.0205044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/18/2018] [Indexed: 11/18/2022] Open
Abstract
Activation studies with positron emission tomography (PET) in auditory implant users explained some of the mechanisms underlying the variability of achieved speech comprehension. Since future developments of auditory implants will include studies in rodents, we aimed to inversely translate functional PET imaging to rats. In normal hearing rats, activity in auditory and non-auditory regions was studied using 18F-fluorodeoxyglucose (18F-FDG) PET with 3 different acoustic conditions: sound attenuated laboratory background, continuous white noise and rippled noise. Additionally, bilateral cochlea ablated animals were scanned. 3D image data were transferred into a stereotaxic standard space and evaluated using volume of interest (VOI) analyses and statistical parametric mapping (SPM). In normal hearing rats alongside the auditory pathway consistent activations of the nucleus cochlearis (NC), olivary complex (OC) and inferior colliculus (IC) were seen comparing stimuli with background. In this respect, no increased activation could be detected in the auditory cortex (AC), which even showed deactivation with white noise stimulation. Nevertheless, higher activity in the AC in normal hearing rats was observed for all 3 auditory conditions against the cochlea ablated status. Vice versa, in ablated status activity in the olfactory nucleus (ON) was higher compared to all auditory conditions in normal hearing rats. Our results indicate that activations can be demonstrated in normal hearing animals based on 18F-FDG PET in nuclei along the central auditory pathway with different types of noise stimuli. However, in the AC missing activation with respect to the background advises the need for more rigorous background noise attenuation for non-invasive reference conditions. Finally, our data suggest cross-modal activation of the olfactory system following cochlea ablation–underlining, that 18F-FDG PET appears to be well suited to study plasticity in rat models for cochlear implantation.
Collapse
Affiliation(s)
- Martin Mamach
- Department of Medical Physics and Radiation Protection, Hannover Medical School, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
- * E-mail:
| | - Mariella Kessler
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Jens P. Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Florian Wilke
- Department of Medical Physics and Radiation Protection, Hannover Medical School, Hannover, Germany
| | - Lilli Geworski
- Department of Medical Physics and Radiation Protection, Hannover Medical School, Hannover, Germany
| | - Frank M. Bengel
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - Simone Kurt
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine CIPMM, Saarland University, Homburg, Germany
| | - Georg Berding
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| |
Collapse
|
2
|
Kessler M, Mamach M, Beutelmann R, Bankstahl JP, Bengel FM, Klump GM, Berding G. Activation in the auditory pathway of the gerbil studied with 18F-FDG PET: effects of anesthesia. Brain Struct Funct 2018; 223:4293-4305. [PMID: 30203305 DOI: 10.1007/s00429-018-1743-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 08/29/2018] [Indexed: 01/20/2023]
Abstract
Here, we present results from an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) study in the Mongolian gerbil, a preferred animal model in auditory research. One major issue in preclinical nuclear imaging, as well as in most of the neurophysiological methods investigating auditory processing, is the need of anesthesia. We compared the usability of two types of anesthesia which are frequently employed in electrophysiology, ketamine/xylazine (KX), and fentanyl/midazolam/medetomidine (FMM), for valid measurements of auditory activation with 18F-FDG PET. Gerbils were placed in a sound-shielding box and injected with 18F-FDG. Two acoustic free-field conditions were used: (1) baseline (no stimulation, 25 dB background noise) and (2) 90 dB frequency-modulated tones (FM). After 40 min of 18F-FDG uptake, a 30 min acquisition was performed using a small animal PET/CT system. Blood glucose levels were measured after the uptake phase before scanning. Standardized uptake value ratios for relevant regions were determined after implementing image and volume of interest templates. Scans demonstrated a significantly higher uptake in the inferior colliculus with FM stimulation compared to baseline in awake subjects (+ 12%; p = 0.02) and with FMM anesthesia (+ 13%; p = 0.0012), but not with KX anesthesia. In non-auditory brain regions, no significant difference was detected. Blood glucose levels were significantly higher under KX compared to FMM anesthesia (17.29 ± 0.42 mmol/l vs. 14.30 ± 1.91 mmol/l; p = 0.024). These results suggest that valid 18F-FDG PET measurements of auditory activation comparable to electrophysiology can be obtained from gerbils during opioid-based anesthesia due to its limited effects on interfering blood glucose levels.
Collapse
Affiliation(s)
- M Kessler
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany
| | - M Mamach
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany.,Department of Medical Physics and Radiation Protection, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - R Beutelmann
- Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany.,Division for animal Physiology and Behaviour Group, Department for Neuroscience, School of Medicine and Health Sciences, University of Oldenburg, Carl von Ossietzky Str. 9-11, 26129, Oldenburg, Germany
| | - J P Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - F M Bengel
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - G M Klump
- Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany.,Division for animal Physiology and Behaviour Group, Department for Neuroscience, School of Medicine and Health Sciences, University of Oldenburg, Carl von Ossietzky Str. 9-11, 26129, Oldenburg, Germany
| | - Georg Berding
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Cluster of Excellence Hearing4all, University of Oldenburg, Oldenburg, Germany.
| |
Collapse
|
4
|
Chen Z, Yuan W. Central plasticity and dysfunction elicited by aural deprivation in the critical period. Front Neural Circuits 2015; 9:26. [PMID: 26082685 PMCID: PMC4451366 DOI: 10.3389/fncir.2015.00026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 05/13/2015] [Indexed: 12/31/2022] Open
Abstract
The acoustic signal is crucial for animals to obtain information from the surrounding environment. Like other sensory modalities, the central auditory system undergoes adaptive changes (i.e., plasticity) during the developmental stage as well as other stages of life. Owing to its plasticity, auditory centers may be susceptible to various factors, such as medical intervention, variation in ambient acoustic signals and lesion of the peripheral hearing organ. There are critical periods during which auditory centers are vulnerable to abnormal experiences. Particularly in the early postnatal development period, aural inputs are essential for functional maturity of auditory centers. An aural deprivation model, which can be achieved by attenuating or blocking the peripheral acoustic afferent input to the auditory center, is ideal for investigating plastic changes of auditory centers. Generally, auditory plasticity includes structural and functional changes, some of which can be irreversible. Aural deprivation can distort tonotopic maps, disrupt the binaural integration, reorganize the neural network and change the synaptic transmission in the primary auditory cortex or at lower levels of the auditory system. The regulation of specific gene expression and the modified signal pathway may be the deep molecular mechanism of these plastic changes. By studying this model, researchers may explore the pathogenesis of hearing loss and reveal plastic changes of the auditory cortex, facilitating the therapeutic advancement in patients with severe hearing loss. After summarizing developmental features of auditory centers in auditory deprived animals and discussing changes of central auditory remodeling in hearing loss patients, we aim at stressing the significant of an early and well-designed auditory training program for the hearing rehabilitation.
Collapse
Affiliation(s)
- Zhiji Chen
- Department of Otorhinolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University Chongqing, China
| | - Wei Yuan
- Department of Otorhinolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University Chongqing, China
| |
Collapse
|
5
|
Sequential [(18)F]FDG µPET whole-brain imaging of central vestibular compensation: a model of deafferentation-induced brain plasticity. Brain Struct Funct 2014; 221:159-70. [PMID: 25269833 DOI: 10.1007/s00429-014-0899-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
Abstract
Unilateral inner ear damage is followed by a rapid behavioural recovery due to central vestibular compensation. In this study, we utilized serial [(18)F]Fluoro-deoxyglucose ([(18)F]FDG)-µPET imaging in the rat to visualize changes in brain glucose metabolism during behavioural recovery after surgical and chemical unilateral labyrinthectomy, to determine the extent and time-course of the involvement of different brain regions in vestibular compensation and test previously described hypotheses of underlying mechanisms. Systematic patterns of relative changes of glucose metabolism (rCGM) were observed during vestibular compensation. A significant asymmetry of rCGM appeared in the vestibular nuclei, vestibulocerebellum, thalamus, multisensory vestibular cortex, hippocampus and amygdala in the acute phase of vestibular imbalance (4 h). This was followed by early vestibular compensation over 1-2 days where rCGM re-balanced between the vestibular nuclei, thalami and temporoparietal cortices and bilateral rCGM increase appeared in the hippocampus and amygdala. Subsequently over 2-7 days, rCGM increased in the ipsilesional spinal trigeminal nucleus and later (7-9 days) rCGM increased in the vestibulocerebellum bilaterally and the hypothalamus and persisted in the hippocampus. These systematic dynamic rCGM patterns during vestibular compensation, were confirmed in a second rat model of chemical unilateral labyrinthectomy by serial [(18)F]FDG-µPET. These findings show that deafferentation-induced plasticity after unilateral labyrinthectomy involves early mechanisms of re-balancing predominantly in the brainstem vestibular nuclei but also in thalamo-cortical and limbic areas, and indicate the contribution of spinocerebellar sensory inputs and vestibulocerebellar adaptation at the later stages of behavioural recovery.
Collapse
|
6
|
Tseng LTL, Lin CL, Tzen KY, Chang SC, Chang MF. LMBD1 protein serves as a specific adaptor for insulin receptor internalization. J Biol Chem 2013; 288:32424-32432. [PMID: 24078630 DOI: 10.1074/jbc.m113.479527] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Energy homeostasis is crucial for maintaining normally functioning cells; disturbances in this balance often cause various diseases. The limb region 1 (LMBR1) domain containing 1 gene (lmbrd1) encodes the LMBD1 protein that possesses 9 putative transmembrane domains. LMBD1 has been suggested to be involved in the lysosome in aiding the export of cobalamin. In this study, we determined that LMBD1 plays a regulatory role in the plasma membrane. A micro-positron emission tomography analysis showed that a single-allele knock-out of lmbrd1 increased the (18)F-fluorodeoxyglucose uptake in murine hearts. In addition, the knockdown of lmbrd1 resulted in an up-regulated signaling of the insulin receptor (IR) and its downstream signaling molecule, Akt. Confocal and live total internal reflection fluorescence microscopy showed that LMBD1 co-localized and co-internalized with clathrin and the IR, but not with the transferrin receptor. The results of the mutation analysis and phenotypic rescue experiments indicate that LMBD1 interacts with adaptor protein-2 and is involved in the unique clathrin-mediated endocytosis of the IR. LMBD1 selectively interacts with the IR. The knockdown of lmbrd1 attenuated IR endocytosis, resulting in the perturbation of the IR recycling pathway and consequential enhancement of the IR signaling cascade. In summary, LMBD1 plays an imperative role in mediating and regulating the endocytosis of the IR.
Collapse
Affiliation(s)
| | | | - Kai-Yuan Tzen
- the Department of Nuclear Medicine, National Taiwan University Hospital, Taipei 10041, Taiwan
| | - Shin C Chang
- the Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Ming-Fu Chang
- From the Institute of Biochemistry and Molecular Biology.
| |
Collapse
|
7
|
Lin CJ, Tai Y, Huang MT, Tsai YF, Hsu HJ, Tzen KY, Liou HH. Cellular localization of the organic cation transporters, OCT1 and OCT2, in brain microvessel endothelial cells and its implication for MPTP transport across the blood-brain barrier and MPTP-induced dopaminergic toxicity in rodents. J Neurochem 2010; 114:717-27. [DOI: 10.1111/j.1471-4159.2010.06801.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|