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Hypoxia and brain development
C Nyakas1, B Buwalda, P G Luiten
1Department of Animal Physiology, University of Groningen, Haren, The Netherlands.
Insights
Perinatal hypoxia and anoxia negatively impact brain development and function across the lifespan. Calcium channel blockers like nimodipine show potential in mitigating these adverse effects on behavior and neurochemistry.
Area of Science:
- Neuroscience
- Developmental Biology
- Perinatal Medicine
Background:
- Hypoxia poses a significant threat to brain function from fetal development through senescence.
- Perinatal hypoxia and anoxia can lead to long-term neurodevelopmental deficits and cognitive decline during aging.
Purpose of the Study:
- To compare the effects of fetal chronic hypoxia and neonatal anoxia on behavior across the lifespan.
- To investigate the cellular mechanisms underlying perinatal hypoxia's impact on neuronal development and function.
- To evaluate the neuroprotective potential of calcium channel blockers.
Main Methods:
- Review of behavioral paradigms including novelty-induced and learning behaviors.
- Assessment of neurochemical changes, including cholinergic fiber ingrowth and hippocampal ChAT activity.
- Pharmacological intervention with nimodipine (L-type calcium channel blocker) and measurement of calcium-binding proteins.
Main Results:
- Prenatal hypoxia delays cholinergic and serotonergic fiber development and enhances axonal degeneration during aging.
- Neonatal anoxia alters hippocampal cholinergic activity and muscarinic receptor binding.
- Nimodipine treatment attenuated adverse behavioral and neurochemical outcomes and promoted the development of calcium-binding proteins.
Conclusions:
- Altered axonal development and cholinergic function are key mechanisms for perinatal hypoxia-induced behavioral deficits.
- Maintaining calcium homeostasis is crucial for neuronal development following perinatal hypoxic insults.
- Pharmacological modulation of calcium channels may offer a therapeutic strategy against perinatal hypoxia-induced brain damage.
Abstract:
Hypoxia threatens brain function during the entire life-span starting from early fetal age up to senescence. This review compares the short-term, long-term and life-spanning effects of fetal chronic hypoxia and neonatal anoxia on several behavioural paradigms including novelty-induced spontaneous and learning behaviours. Furthermore, it reveals that perinatal hypoxia is an additional threat to neurodegeneration and decline of cognitive and other behaviours during the aging process. Prenatal hypoxia evokes a temporary delay of ingrowth of cholinergic and serotonergic fibres into the hippocampus and neocortex, and causes an enhanced neurodegeneration of 5-HT-ir axons during aging. Neonatal anoxia suppresses hippocampal ChAT activity and up-regulates muscarinic receptor sites for 3H-QNB and 3H-pirenzepine binding in the hippocampus in the early postnatal age. The altered development of axonal arborization and pre- and postsynaptic cholinergic functions may be an important underlying mechanism to explain the behavioural deficits. As far as the cellular mechanisms of perinatal hypoxia is concerned, our primary aim was to study the putative importance of Ca2+ homeostasis of developing neurons by means of pharmacological interventions and by measuring the development of immunoexpression of Ca(2+)-binding proteins. We assessed that nimodipine, an L-type calcium channel blocker, prevented or attenuated the adverse behavioural and neurochemical effects of perinatal hypoxias, while it enhanced the early postnatal development of ir-Ca(2+)-binding proteins. The results are discussed in the context of different related research areas on brain development and hypoxia and ischaemia.