title: Effects of topiramate on the prepulse inhibition of the acoustic startle in rats.
abstract: The anticonvulsant topiramate (TPM) has been recently proposed as a novel adjuvant therapy for bipolar disorder and schizophrenia, yet its efficacy remains controversial. As both disorders are characterized by gating deficits, we tested the effects of TPM on the behavioral paradigm of prepulse inhibition (PPI) of the acoustic startle response, a validated animal model of sensorimotor gating. TPM (10, 18, 32, 58, 100 mg/kg, intraperitoneal, i.p.) enhanced PPI in rats in a dose-dependent fashion, prevented the PPI reduction mediated by the dopaminergic agonist apomorphine (0.25 mg/kg, subcutaneous, s.c.) and potentiated the effects of the antipsychotic drugs haloperidol (0.05, 0.1 mg/kg, i.p.) and clozapine (2.5, 5 mg/kg, i.p.). Conversely, TPM elicited no significant effect on the PPI disruption mediated by the NMDA receptor antagonist dizocilpine (0.05, 0.1 mg/kg, s.c.) and surprisingly antagonized the attenuation of dizocilpine-induced PPI disruption mediated by clozapine (5 mg/kg, i.p.). Our results suggest that TPM may exert diverse actions on the neural substrates of sensorimotor gating. While the pharmacological mechanisms of such effects are still elusive, our findings might contribute to shed light on some controversies on the therapeutic action of TPM, and point to this drug as a putative novel adjuvant therapy for some clusters of gating disturbances.
authors.affiliation: Department of Neuroscience, Bernard B. Brodie, University of Cagliari, Cagliari, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Frau
authors.forename: Marco
authors.initials: M
authors.lastname: Orrù
authors.forename: Mauro
authors.initials: M
authors.lastname: Fà
authors.forename: Alberto
authors.initials: A
authors.lastname: Casti
authors.forename: Mario
authors.initials: M
authors.lastname: Manunta
authors.forename: Nicola
authors.initials: N
authors.lastname: Fais
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Mereu
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Gessa
authors.forename: Marco
authors.initials: M
authors.lastname: Bortolato
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D014150:Antipsychotic Agents / Q000819:agonists; D001714:Bipolar Disorder / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005632:Fructose / Q000031:analogs & derivatives* / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects* / Q000502:physiology; D012559:Schizophrenia / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D000077236:Topiramate
chemical_list: D000927:Anticonvulsants; D014150:Antipsychotic Agents; D018491:Dopamine Agonists; D018691:Excitatory Amino Acid Antagonists; D000077236:Topiramate; D005632:Fructose; D018698:Glutamic Acid; D004298:Dopamine