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Dopaminergic stimulation disrupts sensorimotor gating in the rat
R S Mansbach1, M A Geyer, D L Braff
1Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093.
Psychopharmacology
|January 1, 1988
Summary
Dopamine-increasing drugs like apomorphine and amphetamine disrupt prepulse inhibition, a measure of sensory gating. This suggests dopaminergic overactivity may underlie schizophrenia
Area of Science:
- Neuropharmacology
- Behavioral Neuroscience
- Psychopharmacology
Background:
- Prepulse inhibition (PPI) is a cross-species phenomenon where a weak prestimulus modifies reflex responses.
- PPI is relevant to understanding information processing deficits in schizophrenia.
- Dopaminergic pathways are implicated in sensorimotor gating and schizophrenia.
Purpose of the Study:
- To investigate the neuropharmacological mechanisms of prepulse inhibition (PPI).
- To examine the effects of dopaminergic agents on PPI in rats.
- To explore the relevance of PPI to schizophrenic psychopathology.
Main Methods:
- Rats received apomorphine or d-amphetamine to assess effects on acoustic startle response PPI.
- Haloperidol, a D2 antagonist, was used to block drug effects.
- PPI was tested under varying startle stimulus intensities and with chronic amphetamine administration.
Main Results:
- Both apomorphine and d-amphetamine significantly reduced PPI, indicating impaired sensorimotor gating.
- Haloperidol blocked the effect of apomorphine on PPI.
- Chronic amphetamine administration also led to a loss of PPI without tolerance.
Conclusions:
- Dopaminergic overactivity is linked to deficits in sensorimotor gating, as measured by PPI.
- Findings support the hypothesis that information processing deficits contribute to schizophrenia symptoms.
- These results highlight the potential role of D2 dopamine antagonists in treating psychosis.