Fear-potentiated startle response in mice: Genetic analysis of the C57BL/6J and DBA/2J intercross

Citation
Ja. Mccaughran et al., Fear-potentiated startle response in mice: Genetic analysis of the C57BL/6J and DBA/2J intercross, PHARM BIO B, 65(2), 2000, pp. 301-312
Citations number
61
Categorie Soggetti
Neurosciences & Behavoir
Journal title
PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR
ISSN journal
00913057 → ACNP
Volume
65
Issue
2
Year of publication
2000
Pages
301 - 312
Database
ISI
SICI code
0091-3057(200002)65:2<301:FSRIMG>2.0.ZU;2-V
Abstract
The role of genetic factors in the fear-potentiated startle (FPS) response was examined in the inbred C57BL/6J (B6) and DBA/2J (D2) mouse strains. Mic e in the D2 strain displayed a significant potentiation in the acoustic sta rtle response (ASR) when presented with a visual condition stimulus (CS) pr eviously paired with an aversive unconditioned stimulus (US). The maximal F PS response was observed following 20 conditioning trials but a near maxima l response was noted following as few as five trials. Forty conditioning tr ials produced a significant reduction in the FPS response that may be relat ed to overtraining. The FPS response in the B6 strain was significantly low er than the D2 strain, regardless of the number of conditioning trials. The contrasting FPS responses were not related to differences in auditory sens itivity known to exist between these strains. Analysis of a full Mendelian cross formed from the B6 and D2 strains found that the FPS response was a h ighly heritable trait, best described by a simple additive model of inherit ance and with a broad-sense heritability of 0.46. The distribution of the F PS response in F2 hybrids formed from the intercross of the D2 and B6 strai ns was continuous which suggests a multigenic substrate. The light + noise and noise-alone trial types were highly correlated, but no association was detected between the baseline ASR amplitude and the FPS response. Mice from the phenotypic extremes of the F2 distribution displayed FPS responses tha t were more extreme than either of the progenitor strains. However, both ba seline startle amplitude and the salience of auditory stimuli did not diffe r in these groups. The results of this study confirm an early report by Fal ls et al. (1997), and provide additional quantitative genetics information necessary for the eventual mapping of the chromosomal regions or genes asso ciated with the FPS response in mice. (C) 2000 Elsevier Science Inc.