Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
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Neuropsychopharmacology · Mar 2006
Comparative StudyEffects of background and prepulse characteristics on prepulse inhibition and facilitation: implications for neuropsychiatric research.
Both prepulse inhibition (PPI) and prepulse facilitation (PPF) deficits have been reported in schizophrenia patients, but the use of different experimental parameters across laboratories makes direct comparisons of results difficult. We assessed the effects of different parameters on PPI and PPF in normal subjects. ⋯ Paradigmatic differences appear likely to be responsible for divergent findings in studies of PPI and PPF in normal and schizophrenia subjects. The present study should guide investigators in the selection of parameters for assessing PPI and PPF in studies of normal subjects and schizophrenia patients. Attention to the 4 factors of 1) background noise, 2) prepulse duration, 3) frequency, and 4) interval will facilitate comparability of results across different laboratories, especially when using PPI/PPF in schizophrenia research as neural substrate probes, as biomarkers, and as endophenotypes.
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Neuropsychopharmacology · Mar 2006
Significant association of catechol-O-methyltransferase (COMT) haplotypes with nicotine dependence in male and female smokers of two ethnic populations.
The catechol-O-methyltransferase (COMT) gene plays a prominent role in dopaminergic circuits central to drug reward. Allelic variants within the COMT gene are therefore potential candidates for examining interindividual differences in vulnerability to nicotine dependence (ND). We analyzed five single nucleotide polymorphisms (SNPs), including the Val/Met variant (rs4680), which results in a three- to four-fold difference in enzyme activity within COMT, for association with the three ND measures, SQ, HSI, and FTND, in 602 nuclear families of African-American (AA) or European-American (EA) origin. ⋯ Moreover, we found a major high-risk T-A-T haplotype (frequency 56.7%) that showed significant association with the three ND measures in EA males. Further examination of two protective haplotypes, A-G-T in AAs and T-G-T in EAs, indicated that the low COMT enzyme activity Met allele is protective to become nicotine dependent. In summary, our results provide evidence for a role of COMT in the susceptibility to ND and further confirm that its effect is ethnic and gender specific.
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Neuropsychopharmacology · Mar 2006
A mouse model system for genetic analysis of sociability: C57BL/6J versus BALB/cJ inbred mouse strains.
Impairments in social behaviors are highly disabling symptoms of autism, schizophrenia, and other psychiatric disorders. Mouse model systems are useful for identifying the many genes and environmental factors likely to affect complex behaviors, such as sociability (the tendency to seek social interaction). To progress toward developing such a model system, we tested the hypothesis that C57BL/6J inbred mice show higher levels of sociability than BALB/cJ inbred mice. ⋯ We propose that C57BL/6J and BALB/cJ mice will be a useful mouse model system for future genetic and neurobiological studies of sociability.