Changes in Connexin-43 Expression and Neuropil Ultrastructure in the Cerebral Cortex of Bats During the Sleep–Wake Cycle
- 1Research Laboratory “Medical Digital Images Based on the Basic Model”, Department of Bioengineering, Institute of Living Systems, Don State Technical University, Rostov-on-Don 344000, Russia
- 2Research Laboratory of Pharmacology and Experimental Pathology, Institute of Living Systems, Don State Technical University, Rostov-on-Don 344000, Russia
Abstract
Sleep maintains central nervous system homeostasis, but many molecular mechanisms of sleep–wake regulation remain poorly understood. Connexin-43 (Cx43), the astrocytic gap junction protein, supports neuroglial communication, yet its role in physiological sleep is little studied. Here, we analyzed Cx43 expression, gap junction organization and neuropil ultrastructure in the motor cortex of common noctule bats (Nyctalus noctula) during sleep and wakefulness using confocal microscopy, transmission electron microscopy, semi-automated image analysis, and molecular dynamics. Sleep was associated with higher Cx43 immunoreactivity and with more and larger astrocytic gap-junction plaques than wakefulness. Across neuropil fields, synaptic, process and mitochondrial counts and total active-zone length were higher during wakefulness, and mean mitochondrial profiles were larger during sleep; after averaging within animals, only total active-zone length remained significantly greater during wakefulness. More perisynaptic astrocytic process (PAP) profiles contacted synapses during wakefulness, whereas individual PAPs were larger during sleep; both contrasts remained significant after animal-level averaging. As a secondary, hypothesis-generating analysis, we simulated histidine protonation of the Cx43 hemichannel as a simplified model of acidic conditions. Cerebral pH was not measured, and the simulations do not explain the sleep-associated Cx43 increase. In silico, protonation reduced conformational flexibility and narrowed the central and extracellular pore regions.
Related
- Dysregulation of Expression of Nicotinic Acetylcholine Receptors and Ly6/uPAR Proteins in the Cingulate Gyrus of the Cerebral Cortex of Patients with Alzheimer's Disease.
- A family-wide atlas of human connexin docking compatibility
- Exploratory analysis of cell-free miRNA expression changes in patients with isolated first seizure and new-onset epilepsy
- Lipids intercalate and mediate multi-channel assemblies of connexin-46/50 gap junctions
- Schizophrenia-associated gut microbiota are linked to reduced colonic PRODH expression and behavioral changes in mice.
BibTeX
@article{rodkin2026changes,
title = {{Changes in Connexin-43 Expression and Neuropil Ultrastructure in the Cerebral Cortex of Bats During the Sleep–Wake Cycle}},
author = {Stanislav Rodkin and Stanislav Bachurin and Rozaliia Nabiullina and Sergei Shebeko and Alexander Logvinov and Chizaram Nwosu and Evgeniya Kirichenko},
journal = {International Journal of Molecular Sciences},
year = {2026},
month = oct,
doi = {10.3390/ijms27209171},
url = {https://www.mdpi.com/1422-0067/27/20/9171},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Changes in Connexin-43 Expression and Neuropil Ultrastructure in the Cerebral Cortex of Bats During the Sleep–Wake Cycle
AU - Stanislav Rodkin
AU - Stanislav Bachurin
AU - Rozaliia Nabiullina
AU - Sergei Shebeko
AU - Alexander Logvinov
AU - Chizaram Nwosu
AU - Evgeniya Kirichenko
PY - 2026
DA - 2026/10/01
JO - International Journal of Molecular Sciences
DO - 10.3390/ijms27209171
UR - https://www.mdpi.com/1422-0067/27/20/9171
AB - Sleep maintains central nervous system homeostasis, but many molecular mechanisms of sleep–wake regulation remain poorly understood. Connexin-43 (Cx43), the astrocytic gap junction protein, supports neuroglial communication, yet its role in physiological sleep is little studied. Here, we analyzed Cx43 expression, gap junction organization and neuropil ultrastructure in the motor cortex of common noctule bats (Nyctalus noctula) during sleep and wakefulness using confocal microscopy, transmission electron microscopy, semi-automated image analysis, and molecular dynamics. Sleep was associated with higher Cx43 immunoreactivity and with more and larger astrocytic gap-junction plaques than wakefulness. Across neuropil fields, synaptic, process and mitochondrial counts and total active-zone length were higher during wakefulness, and mean mitochondrial profiles were larger during sleep; after averaging within animals, only total active-zone length remained significantly greater during wakefulness. More perisynaptic astrocytic process (PAP) profiles contacted synapses during wakefulness, whereas individual PAPs were larger during sleep; both contrasts remained significant after animal-level averaging. As a secondary, hypothesis-generating analysis, we simulated histidine protonation of the Cx43 hemichannel as a simplified model of acidic conditions. Cerebral pH was not measured, and the simulations do not explain the sleep-associated Cx43 increase. In silico, protonation reduced conformational flexibility and narrowed the central and extracellular pore regions.
SN - 1422-0067
ER -