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Updated: May 26, 2026

Habituation and Prepulse Inhibition of Acoustic Startle in Rodents
Published on: September 1, 2011
Adenosine A(2A) Receptor Antagonists Do Not Disrupt Rodent Prepulse Inhibition: An Improved Side Effect Profile in
Carina J Bleickardt1, Abigail L Lashomb, Carrie E Merkel
1Department of In Vivo Pharmacology, Neuroscience, Merck Research Laboratories, 2015 Galloping Hill Road, K-15-1600, Kenilworth, NJ 07033, USA.
Abstract:
Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra. Current treatments for PD focus on dopaminergic therapies, including L-dopa and dopamine receptor agonists. However, these treatments induce neuropsychiatric side effects. Psychosis, characterized by delusions and hallucinations, is one of the most serious such side effects. Adenosine A(2A) receptor antagonism is a nondopaminergic treatment for PD with clinical and preclinical efficacy. The present studies assessed A(2A) antagonists SCH 412348 and istradefylline in rodent prepulse inhibition (PPI), a model of psychosis. Dopamine receptor agonists pramipexole (0.3-3 mg/kg), pergolide (0.3-3 mg/kg), and apomorphine (0.3-3 mg/kg) significantly disrupted PPI; ropinirole (1-30 mg/kg) had no effect; L-dopa (100-300 mg/kg) disrupted rat but not mouse PPI. SCH 412348 (0.3-3 mg/kg) did not disrupt rodent PPI; istradefylline (0.1-1 mg/kg) marginally disrupted mouse but not rat PPI. These results suggest that A(2A) antagonists, unlike dopamine agonists, have an improved neuropsychiatric side effect profile.
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