title: Enhancement of prepulse inhibition of startle in mice by the H3 receptor antagonists thioperamide and ciproxifan.
abstract: Histamine H3 receptor antagonists/inverse agonists have been proposed as potential therapeutic agents for the treatment of a number of neurological disorders ranging from attention deficit hyperactivity disorder and Alzheimer's disease to narcolepsy and schizophrenia. With respect to the latter, schizophrenic patients typically exhibit impaired prepulse inhibition (PPI) of startle, a reflex that can be modeled in many animal species. Certain strains of mice naturally display poor PPI and it was recently suggested that these mice might offer a new way to screen for novel antipsychotic compounds. To examine whether H3 receptor antagonists might enhance PPI in mice with naturally occurring deficits, DBA/2 and C57BL/6 were tested in a startle paradigm with three prepulse intensities: 5, 10 and 15 dB above background. Both thioperamide and ciproxifan enhanced PPI in the DBA/2 strain; thioperamide also showed a trend towards enhancing PPI in C57BL/6. Risperidone, an atypical antipsychotic, enhanced PPI in both the DBA/2 and the C57BL/6 strain. These data confirm previous reports describing a natural deficit in PPI in some mouse strains that is amenable to enhancement with known antipsychotics. Further, these data suggest that H3 receptor antagonists/inverse agonists have anti-psychotic potential for disorders such as schizophrenia.
authors.affiliation: Neuroscience Research, Abbott Laboratories, AP9A, 100 Abbott Park, Abbott Park, IL 60064-6115, USA. kaitlin.e.browman@abbott.com
authors.forename: Kaitlin E
authors.initials: KE
authors.lastname: Browman
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Komater
authors.forename: Peter
authors.initials: P
authors.lastname: Curzon
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Rueter
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Hancock
authors.forename: Michael W
authors.initials: MW
authors.lastname: Decker
authors.forename: Gerard B
authors.initials: GB
authors.lastname: Fox
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006633:Histamine Antagonists / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D007266:Inhibition, Psychological; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010880:Piperidines / Q000494:pharmacology*; D018100:Receptors, Histamine H3 / Q000502:physiology*; D013216:Reflex, Startle / Q000187:drug effects* / Q000528:radiation effects; D018967:Risperidone / Q000494:pharmacology; D013045:Species Specificity
chemical_list: D018492:Dopamine Antagonists; D006633:Histamine Antagonists; D007093:Imidazoles; D010880:Piperidines; D018100:Receptors, Histamine H3; C115705:ciproxifan; C052075:thioperamide; D018967:Risperidone