TY  - JOUR
A1  - Pozzi, Nicoló Gabriele
A1  - Bolzoni, Francesco
A1  - Biella, Gabriele Eliseo Mario
A1  - Pezzoli, Gianni
A1  - Ip, Chi Wang
A1  - Volkmann, Jens
A1  - Cavallari, Paolo
A1  - Asan, Esther
A1  - Isaias, Ioannis Ugo
T1  - Brain noradrenergic innervation supports the development of Parkinson’s tremor: a study in a reserpinized rat model
JF  - Cells
N2  - The pathophysiology of tremor in Parkinson’s disease (PD) is evolving towards a complex alteration to monoaminergic innervation, and increasing evidence suggests a key role of the locus coeruleus noradrenergic system (LC-NA). However, the difficulties in imaging LC-NA in patients challenge its direct investigation. To this end, we studied the development of tremor in a reserpinized rat model of PD, with or without a selective lesioning of LC-NA innervation with the neurotoxin DSP-4. Eight male rats (Sprague Dawley) received DSP-4 (50 mg/kg) two weeks prior to reserpine injection (10 mg/kg) (DR-group), while seven male animals received only reserpine treatment (R-group). Tremor, rigidity, hypokinesia, postural flexion and postural immobility were scored before and after 20, 40, 60, 80, 120 and 180 min of reserpine injection. Tremor was assessed visually and with accelerometers. The injection of DSP-4 induced a severe reduction in LC-NA terminal axons (DR-group: 0.024 ± 0.01 vs. R-group: 0.27 ± 0.04 axons/um\(^2\), p < 0.001) and was associated with significantly less tremor, as compared to the R-group (peak tremor score, DR-group: 0.5 ± 0.8 vs. R-group: 1.6 ± 0.5; p < 0.01). Kinematic measurement confirmed the clinical data (tremor consistency (% of tremor during 180 s recording), DR-group: 37.9 ± 35.8 vs. R-group: 69.3 ± 29.6; p < 0.05). Akinetic–rigid symptoms did not differ between the DR- and R-groups. Our results provide preliminary causal evidence for a critical role of LC-NA innervation in the development of PD tremor and foster the development of targeted therapies for PD patients.
KW  - Parkinson’s disease
KW  - tremor
KW  - locus coeruleus
KW  - noradrenaline
KW  - reserpinized rat model
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357721
SN  - 2073-4409
VL  - 12
IS  - 21
ER  - 
TY  - JOUR
A1  - Capetian, Philipp
A1  - Müller, Lorenz
A1  - Volkmann, Jens
A1  - Heckmann, Manfred
A1  - Ergün, Süleyman
A1  - Wagner, Nicole
T1  - Visualizing the synaptic and cellular ultrastructure in neurons differentiated from human induced neural stem cells - an optimized protocol
JF  - International Journal of Molecular Sciences
N2  - The size of the synaptic subcomponents falls below the limits of visible light microscopy. Despite new developments in advanced microscopy techniques, the resolution of transmission electron microscopy (TEM) remains unsurpassed. The requirements of tissue preservation are very high, and human post mortem material often does not offer adequate quality. However, new reprogramming techniques that generate human neurons in vitro provide samples that can easily fulfill these requirements. The objective of this study was to identify the culture technique with the best ultrastructural preservation in combination with the best embedding and contrasting technique for visualizing neuronal elements. Two induced neural stem cell lines derived from healthy control subjects underwent differentiation either adherent on glass coverslips, embedded in a droplet of highly concentrated Matrigel, or as a compact neurosphere. Afterward, they were fixed using a combination of glutaraldehyde (GA) and paraformaldehyde (PFA) followed by three approaches (standard stain, Ruthenium red stain, high contrast en-bloc stain) using different combinations of membrane enhancing and contrasting steps before ultrathin sectioning and imaging by TEM. The compact free-floating neurospheres exhibited the best ultrastructural preservation. High-contrast en-bloc stain offered particularly sharp staining of membrane structures and the highest quality visualization of neuronal structures. In conclusion, compact neurospheres growing under free-floating conditions in combination with a high contrast en-bloc staining protocol, offer the optimal preservation and contrast with a particular focus on visualizing membrane structures as required for analyzing synaptic structures.
KW  - transmission electron microscopy
KW  - human neurons
KW  - induced neural stem cells
KW  - synapse
KW  - synaptic vesicles
KW  - high contrast
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236053
SN  - 1422-0067
VL  - 21
IS  - 5
ER  -