title: Ondansetron results in improved auditory gating in DBA/2 mice through a cholinergic mechanism.
abstract: The 5-HT(3) receptor antagonist, ondansetron, has been shown to correct the auditory gating deficit in medicated schizophrenia patients. Inhibition of 5-HT(3) receptors releases acetylcholine, the endogenous ligand for nicotinic acetylcholine receptors. The schizophrenia-related auditory gating deficit is modulated, in part, by nicotinic acetylcholine receptors, as is the mouse (DBA/2) model of the deficit. The present study assessed the effects of both acute and chronically administered ondansetron on auditory gating in DBA/2 mice. Auditory gating is defined as a decrease in amplitude of response to the second of a paired identical auditory stimulus presented 0.5 s following an initial auditory stimulus. Acute ondansetron administration at the lowest dose (0.1 mg/kg, IP) tested had no effect, while other doses (0.33 and 1 mg/kg, IP) produced improvements in auditory gating. The improvements were produced through both an increase in response to the first auditory stimulus and a decrease in the response to the second auditory stimulus. Co-administration of an alpha7 nicotinic acetylcholine receptor antagonist, alpha-bungarotoxin, or the alpha4beta2 nicotinic acetylcholine receptor antagonist dihydro-beta-erythroidine, with the 0.33 mg/kg dose of ondansetron blocked the improvement in auditory gating produced by ondansetron alone. There was no difference in response between the chronically injected mice and naive mice. Both showed improved auditory gating, thus, demonstrating no "carry over" effect of daily injections. These data demonstrate that indirect stimulation of nicotinic acetylcholine receptors by ondansetron can improve auditory gating parameters in DBA/2 mice.
authors.affiliation: Department of Psychiatry, University of Colorado Denver, Mail Stop 8344, RC-1 North, 12800 East 19th Ave. Aurora, CO 80045, USA. Kristin.Wildeboer@ucdenver.edu
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Wildeboer
authors.forename: Lijun
authors.initials: L
authors.lastname: Zheng
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Choo
authors.forename: Karen E
authors.initials: KE
authors.lastname: Stevens
mesh_terms: D000161:Acoustic Stimulation; D000704:Analysis of Variance; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D056654:CA3 Region, Hippocampal / Q000187:drug effects* / Q000502:physiology; D004079:Dihydro-beta-Erythroidine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D018733:Nicotinic Antagonists / Q000494:pharmacology; D017294:Ondansetron / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000502:physiology*; D044406:Receptors, Serotonin, 5-HT3 / Q000502:physiology*; D055139:Sensory Gating / Q000187:drug effects* / Q000502:physiology; D012702:Serotonin Antagonists / Q000494:pharmacology
chemical_list: D002038:Bungarotoxins; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D004079:Dihydro-beta-Erythroidine; D017294:Ondansetron