Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Prepulse inhibition (PPI) is the reduction in the startle response that occurs when a weak stimulus (prepulse) precedes a startling stimulus, and is impaired in patients with schizophrenia. Some evidence implicates dopamine D2 receptors in this phenomenon, but other evidence suggests that 5-HT2-, but not D2-, selective agonists are effective at reducing PPI. To better understand the role of the dopaminergic and serotonergic systems in the modulation of PPI, 72 rats were administered amphetamine (3 mg/kg) or vehicle (saline), and either vehicle, the D2 antagonist raclopride (0.05 mg/kg), or the 5-HT2 antagonist ketanserin (2 mg/kg). The rats were presented with startling stimuli alone or startling stimuli paired with prepulses, at different stimulus onset asynchrony (SOA) intervals (10-120 ms). Amphetamine decreased the amount of PPI as well as decreasing the SOA at which maximal PPI occurred. Raclopride blocked the amphetamine-induced decrease in PPI, but had no effect on the SOA of maximal PPI. Ketanserin had no effect on amphetamine-induced changes in PPI. These results indicate that D2 receptors, but not 5-HT2 receptors, are necessary (although not sufficient) for reductions in PPI, and sufficient (although not necessary) for shifts in the SOA of maximum inhibition.

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Poster Number PAsakadakis0566
Keywords: D2 receptors, 5-HT2 receptors, Startle Reflex, stimulant, schizophrenia