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Prenatal haloperidol induces a selective reduction in the expression of plasticity-related genes in neonate rat
1Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007.
Insights
Prenatal exposure to haloperidol, an antipsychotic, reduces plasticity-related gene expression in rat neonate forebrains. This dopamine receptor antagonist impacts offspring development by altering gene expression and cell density in critical brain regions.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Haloperidol is an antipsychotic drug targeting dopamine receptors.
- Prenatal haloperidol administration has known long-term adverse effects on offspring development.
- The underlying mechanisms for these developmental effects are not fully understood.
Purpose of the Study:
- To investigate the molecular and cellular basis of haloperidol's deleterious effects on prenatal development.
- To determine the impact of prenatal haloperidol exposure on gene expression in the neonate rat brain.
- To identify specific brain regions and cellular markers affected by prenatal haloperidol.
Main Methods:
- Prenatal administration of haloperidol to rats.
- Analysis of gene expression in neonate rat forebrain and mesencephalon.
- Measurement of specific neurochemical markers (GABAergic, enkephalinergic, cholinergic).
- Assessment of cell proliferation and density in the striatum.
Main Results:
- Haloperidol selectively reduced plasticity-related gene expression in the neonate forebrain, sparing the mesencephalon.
- GABAergic and enkephalinergic markers were diminished in the forebrain.
- Cell mitotic number and density significantly decreased in the striatum.
- Expression of certain genes (EGFR, GFAP, proto-oncogenes) and a cholinergic marker remained unaltered.
Conclusions:
- Prenatal dopamine receptor blockade by haloperidol critically influences forebrain development.
- Altered expression of plasticity-related genes is a key mechanism underlying these developmental deficits.
- Dopamine receptor occupancy during development plays a crucial role in regulating target cell development.
Abstract:
Haloperidol, a dopamine receptor antagonist clinically used as an antipsychotic drug, induces long-term deleterious effects in offspring development when administered prenatally. However, the basis for this overall response to the drug remains unknown. Here we describe that prenatal administration of haloperidol in rats induces a drastic and selective reduction in the expression of plasticity-related genes in neonate forebrain, but not in mesencephalon. GABAergic and enkephalinergic markers such as glutamic acid decarboxylase activity and mRNA, and preproenkephalin mRNA were also diminished in forebrain. However, the expression of other genes such as epidermal growth factor-receptor, glial fibrillary acidic protein, and several proto-oncogenes (src, fos and myc), and a cholinergic marker such as choline acetyltransferase activity were unaltered. In addition, haloperidol promoted a significant decrease in mitotic cell number and cellular density in the striatum, one of the forebrain regions with the highest dopamine receptor density. These findings suggest that prenatal dopamine receptor occupancy may be a critical factor in controlling the development of forebrain target cells through mechanisms involving changes in the expression of plasticity-related genes.