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Two distinctive apomorphine-induced phenotypes in the Roman high- and low-avoidance rats
Lydia Giménez-Llort1, Toni Cañete, Marc Guitart-Masip
1Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, Institute of Neuroscience, Autonomous University of Barcelona, 08193 Bellaterra, Barcelona, Spain. lgimenez@servet.uab.es
Physiology & Behavior
|September 13, 2005
Summary
Rodent strain differences in behavior reveal genetic risks for dopamine dysfunction. Roman High-Avoidance and Low-Avoidance rats show distinct responses to apomorphine, highlighting varied dopaminergic system functions.
Area of Science:
- Neuroscience
- Behavioral Genetics
- Psychopharmacology
Background:
- Dopaminergic dysfunction is linked to psychosis vulnerability.
- Rodent models, like Roman High-Avoidance (RHA) and Low-Avoidance (RLA) rats, exhibit strain-specific behavioral and dopaminergic differences.
- Understanding these differences aids in modeling psychosis risk.
Purpose of the Study:
- To compare spontaneous activity and apomorphine-induced behaviors across Sprague-Dawley (SD), RHA, and RLA rat strains.
- To investigate strain-specific dopaminergic system sensitivities and functional variations.
- To identify behavioral markers for differential susceptibility to dopaminergic dysfunction.
Main Methods:
- Characterization of spontaneous locomotor activity in SD, RHA, and RLA rats.
- Administration of varying doses of apomorphine (0.067-3 mg/kg) to assess behavioral responses.
- Comparative analysis of locomotor activity, yawning, and stereotyped behaviors across strains.
Main Results:
- Roman strains exhibited higher spontaneous activity than SD rats.
- RHA rats showed increased novelty response and heightened sensitivity to apomorphine, particularly at higher doses (stereotyped behavior).
- RLA rats displayed significant yawning and motor inhibition at low apomorphine doses, suggesting enhanced dopamine receptor function.
Conclusions:
- Distinct behavioral profiles indicate strain-specific presynaptic and postsynaptic dopaminergic function differences.
- These findings provide a basis for future studies on the mechanisms underlying dopaminergic dysfunction risk.
- The study highlights the utility of selectively bred rat strains in dissecting complex neurochemical pathways relevant to psychiatric disorders.
