title: Does genetic BDNF deficiency in rats interact with neurotransmitter control of prepulse inhibition? Implications for schizophrenia.
abstract: Several studies have suggested a role of BDNF in the development of schizophrenia. For example, post-mortem studies have shown significantly reduced levels of BDNF protein expression in the brain of schizophrenia patients. We investigated the relationship between reduced levels of BDNF in the brain and the regulation of prepulse inhibition (PPI), a behavioral endophenotype of schizophrenia. We used BDNF heterozygous mutant rats which display a 50% decrease of mature BDNF protein levels. Previously, we observed normal baseline PPI and responses to the dopamine D1/D2 receptor agonist, apomorphine, in these rats. Here, we focused on the effects of the NMDA receptor antagonist, MK-801, its interaction with mGluR2/3 and mGluR5 receptors, and the PPI response to serotonergic drugs. MK-801 administration caused a dose-dependent reduction of PPI and increase of startle amplitudes. Baseline PPI and the effect of 0.02-0.1mg/kg of MK-801 were not significantly altered in male or female BDNF heterozygous rats, although the MK-801-induced increase in startle levels was reduced. Co-treatment with the mGluR2/3 agonist, LY379,268, or the mGluR5 antagonist, MPEP, did not alter the effect of MK-801 on PPI in controls or BDNF mutant rats. Treatment with the serotonin-1A receptor agonist, 8-OH-DPAT, the serotonin-2A receptor agonist, DOI, or the serotonin releaser, fenfluramine, induced differential effects on PPI and startle but these effects were not different between the genotypes. These results show that a significant decrease of BDNF protein expression does not lead to reduced PPI at baseline or changes in the regulation of PPI via NMDA receptors or serotonergic mechanisms. These findings in a genetic rat model of BDNF deficiency do not support a role for similar reductions of BDNF levels in schizophrenia in the disruption of PPI, widely reported as an endophenotype of the illness. The potential implications of these results for our understanding of changes in PPI and BDNF expression in schizophrenia are discussed.
authors.affiliation: School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia; Department of Pharmacology, University of Melbourne, Victoria, Australia; The College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia. Electronic address: m.vandenbuuse@latrobe.edu.au.
authors.forename: Maarten
authors.initials: M
authors.lastname: van den Buuse
authors.affiliation: School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia; Institute of Psychology, University of Luebeck, Luebeck, Germany.
authors.forename: Davina
authors.initials: D
authors.lastname: Biel
authors.affiliation: School of Psychology and Public Health, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Radscheit
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000172:deficiency* / Q000235:genetics*; D015331:Cohort Studies; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D008297:Male; D008698:Mesylates / Q000494:pharmacology; D009154:Mutation / Q000235:genetics*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D065808:Prepulse Inhibition / Q000187:drug effects / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D011922:Rats, Mutant Strains; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: C434605:5,21 - 12,17-dimetheneo-18H-dibenzo(i,o)pyrrolo(3,4-1)(1,8)diazacyclohexandecine-18,10(19H)dione,8((dimethylamino)methyl)-6,7,8,9,10,11-hexahydro,monomethanesulfonate; D019208:Brain-Derived Neurotrophic Factor; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D008698:Mesylates; D018377:Neurotransmitter Agents; D011725:Pyridines; D011758:Pyrroles; D017366:Serotonin Receptor Agonists; D016291:Dizocilpine Maleate; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C121465:6-methyl-2-(phenylethynyl)pyridine
keywords: BDNF heterozygous rats; Brain-derived neurotrophic factor; NMDA receptors; Prepulse inhibition; Serotonin release; Serotonin-1A receptors; Serotonin-2A receptors