Cognitive and Socio-Emotional Deficits in Platelet-Derived Growth Factor Receptor-β Gene Knockout Mice

Platelet-derived growth factor (PDGF) is a potent mitogen. Extensive in vivo studies of PDGF and its receptor (PDGFR) genes have reported that PDGF plays an important role in embryogenesis and development of the central nervous system (CNS). Furthermore, PDGF and the β subunit of the PDGF receptor (PDGFR-β) have been reported to be associated with schizophrenia and autism. However, no study has reported on the effects of PDGF deletion on mice behavior. Here we generated novel mutant mice (PDGFR-β KO) in which PDGFR-β was conditionally deleted in CNS neurons using the Cre/loxP system. Mice without the Cre transgene but with floxed PDGFR-β were used as controls. Both groups of mice reached adulthood without any apparent anatomical defects. These mice were further examined by conducting several behavioral tests for spatial memory, social interaction, conditioning, prepulse inhibition, and forced swimming. The test results indicated that the PDGFR-β KO mice show deficits in all of these areas. Furthermore, an immunohistochemical study of the PDGFR-β KO mice brain indicated that the number of parvalbumin (calcium-binding protein)-positive (i.e., putatively γ-aminobutyric acid-ergic) neurons was low in the amygdala, hippocampus, and medial prefrontal cortex. Neurophysiological studies indicated that sensory-evoked gamma oscillation was low in the PDGFR-β KO mice, consistent with the observed reduction in the number of parvalbumin-positive neurons. These results suggest that PDGFR-β plays an important role in cognitive and socioemotional functions, and that deficits in this receptor may partly underlie the cognitive and socioemotional deficits observed in schizophrenic and autistic patients

Reexamination of CHIME monazite ages for granite samples from Wugongshan and Huangshan, southeastern China

The ages of granite samples from Wugongshan and Huangshan, southeastern China were reexamined with the CHIME method coupled with screening of possibly concordant monazite analyses by the chemical criterion that 0.95<(Ca+Si)/(Th+U+Pb+S)<1.05. The age mapping technique reveals that monazite grains in sample Wugongshan-2, K-feldspar porphyritic muscovite-biotite granite, are chronologically zoned with the dominant central domain. The CHIME ages are 159±12 Ma for the central domain and 129±14 Ma for the marginal domain. Sample Wugongshan-3, coarse-grained peraluminous muscovite-biotite granite, gives a 164±19 Ma monazite age. The CHIME monazite ages for samples Huangshan-9 and -10, within-plate type muscovite-bearing biotite granites, are 130±19 and 138±6 Ma, respectively. Previous CHIME monazite ages, 173±10 Ma for Wugongshan samples and 162±10 Ma for Huangshan samples (Suzuki et al., 2000), appear to have resulted from mixing of concordant and discordant datasets and/or datasets for different age domains. The revised CHIME monazite ages provide chronological constraint for the tectonic evolution of southeastern China including the change from a subduction-related compressive environment to an extensional environment.国立情報学研究所で電子化したコンテンツを使用している