Background: Early stress exposure during neurodevelopmental stages has been linked to some adult
neuropsychiatric disorders. The dopaminergic system which has been implicated in movement and reward system
has been linked to movement and mood disorders when perturbed at early development. This study is designed to
check the mechanisms involved in movement disorders such as dyskinesia, associated with early perturbed
dopaminergic system in the motor cortex.
Methods:Haloperidol was used to block D2R in neonatal albino Wistar rats in utero by administering 20 mg/kg
BW (intraperitoneally) to pregnant adult wistar rats (n=8) in the third week of gestation. Behavioural studies such as
the rotarod test were carried out on the neonatal animals (n=5) to test their motor function at postnatal day twentyeight (P28). Electrophysiological recordings were carried out on the motor cortex (M1) to determine the significance
of D2R inhibition on calcium neural activity. Immunofluorescence was done to demonstrate synaptic vesicle protein
(SV) and microtubule associated protein kinases (MAP K) as a measure of synapses count and microtubule
phosphorylation respectively.
Results: Behavioural studies showed a decline in motor function of animals exposed to haloperidol in utero
compared to the control. This motor deficit was accompanied by a significant increase in the Ca
2+
neural activity of
the motor cortex as shown by electrophysiological recordings. Immunofluorescence staining showed there was
significant increase in the number of MAPK+ and SV+ cells in the motor cortex of haloperidol exposed animals
compared to the control.
Conclusion: These findings showed that early perturbation in dopaminergic system is associated with an
increase in synapses and neuronal density, as well as an increase in phosphorylation of microtubules of neurons in
the motor cortex