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Article: Chronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre‐Bötzinger complex of rats

TitleChronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre‐Bötzinger complex of rats
Authors
Keywordsintermittent hypoxia
neuroplasticity
postsynaptic
respiration
ultrastructure.chronic
Issue Date2020
PublisherFederation of American Societies for Experimental Biology. The Journal's web site is located at http://www.fasebj.org/
Citation
The FASEB Journal, 2020, v. 34 n. 11, p. 14588-14601 How to Cite?
AbstractMitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Botzinger complex (pre-BotC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BotC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BotC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BotC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BotC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.
Persistent Identifierhttp://hdl.handle.net/10722/295840
ISSN
2023 Impact Factor: 4.4
2023 SCImago Journal Rankings: 1.412
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorKang, JJ-
dc.contributor.authorFung, ML-
dc.contributor.authorZhang, K-
dc.contributor.authorLam, CS-
dc.contributor.authorWu, SX-
dc.contributor.authorHuang, XF-
dc.contributor.authorYang, SJ-
dc.contributor.authorWong‐Riley, MTT-
dc.contributor.authorLiu, YY-
dc.date.accessioned2021-02-08T08:14:46Z-
dc.date.available2021-02-08T08:14:46Z-
dc.date.issued2020-
dc.identifier.citationThe FASEB Journal, 2020, v. 34 n. 11, p. 14588-14601-
dc.identifier.issn0892-6638-
dc.identifier.urihttp://hdl.handle.net/10722/295840-
dc.description.abstractMitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Botzinger complex (pre-BotC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BotC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BotC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BotC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BotC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.-
dc.languageeng-
dc.publisherFederation of American Societies for Experimental Biology. The Journal's web site is located at http://www.fasebj.org/-
dc.relation.ispartofThe FASEB Journal-
dc.rightsPreprint This is the pre-peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Postprint This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.-
dc.subjectintermittent hypoxia-
dc.subjectneuroplasticity-
dc.subjectpostsynaptic-
dc.subjectrespiration-
dc.subjectultrastructure.chronic-
dc.titleChronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre‐Bötzinger complex of rats-
dc.typeArticle-
dc.identifier.emailFung, ML: fungml@hku.hk-
dc.identifier.authorityFung, ML=rp00433-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1096/fj.201902141R-
dc.identifier.pmid32910512-
dc.identifier.scopuseid_2-s2.0-85090459357-
dc.identifier.hkuros321232-
dc.identifier.volume34-
dc.identifier.issue11-
dc.identifier.spage14588-
dc.identifier.epage14601-
dc.identifier.isiWOS:000568310700001-
dc.publisher.placeUnited States-

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