Altered pain perception in schizophrenia.

Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
The Lancet (Impact Factor: 39.21). 03/2010; 375(9717):864. DOI: 10.1016/S0140-6736(09)62061-4
Source: PubMed
  • [Show abstract] [Hide abstract]
    ABSTRACT: The outstanding stabilization characteristics of lifted turbulent jet diffusion flames of CH4/CO blended fuels in still air were investigated experimentally by igniting the flame from downstream in the initial condition of a nonreacting fuel jet. In this study, we concentrated on the effects of the shift of outstanding reaction paths on the stabilization characteristics as the composition of the blended CH4/CO is varied. Systematic experiments were conducted using the nonintrusive diagnostics of shuttered laser particle image velocimetry (PIV), OH∗ chemiluminescence, and digital image processing to study the flame stabilization characteristics in terms of the key parameters such as the instantaneous flame-base location, lift-off height, and streamline velocity distribution in the vicinity of the edge flame leading point by varying the exit velocity and blended-fuel concentration. A conditional leading point from shutter PIV measurement is defined to calculate the instantaneous streamline velocity profile at the flame base. For the CO concentration in fuel blends lower than 80%, the stabilization is similar in characteristics to that proposed by the triple flame model. As the CO concentration is increased to 90%, the flame stabilizes on the fuel-rich side and the stabilization characteristics may be related to the maximum burning velocity at the rich equivalence ratio. This is confirmed by the location of the instantaneous flame stabilization point defined by the instantaneous leading point of the lifted flame with respect to the fuel concentration profiles.
    Proceedings of the Combustion Institute 01/2011; 33(1):1655-1662. DOI:10.1016/j.proci.2010.07.030 · 3.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Social isolation rearing in mice after weaning reduces pain sensitivity to acute pain, and this hypoalgesia is mediated by the descending serotonergic pain inhibitory system in which the spinal serotonin (5-HT)1A receptor is involved. However, it is not known whether isolation rearing affects pain sensitivity to neuropathic or inflammatory chronic pain. In this study, we examined the effects of isolation rearing on chronic pain induced by Freund's complete adjuvant (FCA) and partial sciatic nerve ligation using the von Frey test (to assess mechanical allodynia) and the plantar test (to assess thermal hyperalgesia). In the FCA model, isolation rearing reduced mechanical allodynia, but not thermal hyperalgesia. In contrast, isolation rearing had no effect on allodynia or hyperalgesia in the sciatic nerve ligation model. The isolation rearing-induced inhibition of allodynia was alleviated by intrathecal injection of WAY100635, a selective 5-HT1A receptor antagonist. FCA increased 5-HT turnover and decreased 5-HT1A receptor expression in the spinal cord of group-reared mice, while it did not have these effects in isolation-reared mice. These results suggest that FCA suppresses the serotonergic pain inhibitory system selectively in group-reared mice. Moreover, systemic administration of osemozotan, a selective 5-HT1A receptor agonist, inhibited FCA-induced mechanical allodynia in group-reared mice, and this effect of the drug was suppressed by intrathecal injection of WAY100635. Collectively, these findings suggest that isolation rearing selectively reduces FCA-induced mechanical allodynia in mice and that this effect is mediated by the activation of spinal 5-HT1A receptors.
    Pharmacology Biochemistry and Behavior 10/2013; DOI:10.1016/j.pbb.2013.10.017 · 2.82 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study proposes a transdiagnostic framework for delusion development, analysing psychiatric (schizophrenia, bipolar disorder, major depressive disorder) and neurological disorders (stroke, and neurodegenerative diseases) in which delusions are predominant. Our aim is to identify a transdiagnostic core of neural and cognitive alterations associated with delusions across distinct clinical disorders. Reviewed empirical evidence suggests delusions are associated: on the neural level with changes in the ventromedial prefrontal cortex (vmPFC) networks, and on the neuropsychological level with dysfunction in the processes (generation of affective value, the construction of internal models of the world, and the reflection about Self and/or Other's mental states) that these network mediate. The concurrent aberration of all these processes could be critical for the clinical transition to a psychotic delusional state. In particular, delusions could become clinically manifest when (1) stimuli are attributed an aberrant affective salience, that (2) is explained by the patient within distorted explanatory internal models that (3) are poorly inhibited by cognitive control systems. This framework extends the two-factor account of delusion model and suggests that common neural mechanisms for the delusions in psychiatric and in neurological disorders.
    08/2013; 210(3). DOI:10.1016/j.psychres.2013.07.032