Dysfunctional play and dopamine physiology in the Fischer 344 rat

Juvenile Fischer 344 rats are known to be less playful than other inbred strains, although the neurobiological substrate(s) responsible for this phenotype is uncertain. In the present study, Fischer 344 rats were compared to the commonly used outbred Sprague-Dawley strain on several behavioral and physiological parameters in order to ascertain whether the lack of play may be related to compromised activity of brain dopamine (DA) systems. As expected, Fischer 344 rats were far less playful than Sprague-Dawley rats, with Fischer 344 rats less likely to initiate playful contacts with a playful partner and less likely to respond playfully to these contacts. We also found that Fischer 344 rats showed less of a startle response and greater pre-pulse inhibition (PPI), especially at higher prepulse intensities. The increase in PPI seen in the Fischer 344 rat could be due to reduced DA modulation of sensorimotor gating and neurochemical measures were consistent with Fischer 344 rats releasing less DA than Sprague-Dawley rats. Fast scan cyclic voltammetry (FSCV) revealed Fischer 344 rats had less evoked DA release in dorsal and ventral striatal brain slices and high-performance liquid chromatography revealed Fischer 344 rats to have less DA turnover in the striatum and prefrontal cortex. We also found DA-dependent forms of cortical plasticity were deficient in the striatum and prefrontal cortex of the Fischer 344 rat. Taken together, these data indicate that deficits in play and enhanced PPI of Fischer 344 rats may be due to reduced DA modulation of corticostriatal and mesolimbic/mesocortical circuits critical to the execution of these behaviors

No association between the sigma receptor type 1 gene and schizophrenia: results of analysis and meta-analysis of case-control studies

BACKGROUND: Several lines of evidence have supported possible roles of the sigma receptors in the etiology of schizophrenia and mechanisms of antipsychotic efficacy. An association study provided genetic evidence that the sigma receptor type 1 gene (SIGMAR1) was a possible susceptibility factor for schizophrenia, however, it was not replicated by a subsequent study. It is necessary to evaluate further the possibility that the SIGMAR1 gene is associated with susceptibility to schizophrenia. METHODS: A case-control association study between two polymorphisms of the SIGMAR1 gene, G-241T/C-240T and Gln2Pro, and schizophrenia in Japanese population, and meta-analysis including present and previous studies. RESULTS: There was no significant association of any allele or genotype of the polymorphisms with schizophrenia. Neither significant association was observed with hebephrenic or paranoid subtype of schizophrenia. Furthermore, a meta-analysis including the present and previous studies comprising 779 controls and 636 schizophrenics also revealed no significant association between the SIGMAR1 gene and schizophrenia. CONCLUSION: In view of this evidence, it is likely that the SIGMAR1 gene does not confer susceptibility to schizophrenia

Development of an inventory practice for rare lichen species within Thousand Islands National Park

Urbanization, forest fragmentation and climate change have been accelerating the decline of many lichen species populations, especially those which are most sensitive to subtle environmental changes that disrupt ecosystem equilibrium. Due to the many specific habitat requirements of these lichens, they have shown promise as bioindicators for niche habitat areas with unique site characteristics likely important for a variety of red list species. Locating species at risk and bioindicator lichens may therefore in turn reveal areas of high ecological importance where conservation efforts should be increased. Species at risk (SAR) lichen searches are organized by Environment Canada, however efforts have been mainly limited to those with more expertise in lichenology due to the difficulty with lichen field identification as well as limitations with lichen habitat suitability models. It is proposed that the establishment of a rare lichen inventory practice in Canadian national parks would increase the search efforts for lichen species at risk as well as bioindicator species which have high potential for identifying important habitat areas for conservation and ecological integrity monitoring. A rare lichen inventory practice for Thousand Islands National Park (TINP) Resource Conservation staff was developed, focussing on rare lichen species with distribution ranges that envelope the park boundaries. Usnea sp., Lobaria pulmonaria, Physconia subpallida, Leptogium rivulare, Leptogium corticola, Teloschistes chrysophthalmus, and Heterodermia hypoleuca were selected based on their SAR status in Ontario, bioindicator potential and ease of field identification. A lichen guide was compiled, highlighting distinguishing characteristics, significant habitat features, notable Ecological Land Classifications (ELCs), chemical tests, and search tips for each selected lichen species. Calcareous soil, moist deciduous forest and older growth trees were found to be common habitat requirements for many of the selected lichen species and predictive mapping was prepared for Hill Island and Grenadier Island (two locations frequented by TINP Resource Conservation staff) to show how these features could be combined to highlight priority search areas. Hill Island and Grenadier Island were found to contain the majority of the calcareous ELC plots within the TINP boundary and therefore would make excellent preliminary inventory search areas. It is highly recommended that TINP Resource Conservation staff use the enclosed lichen guide to increase familiarity with the selected lichen species and their potential habitat areas at the beginning of each monitoring season. Periodic inventory searches should be conducted in high priority regions and any encounters with the select lichen species should be documented (species name, substrate, date, general location, GPS coordinate, photo). It is highly recommended that other national parks adopt a similar rare lichen inventory practise using customized sets of SAR and bioindicator species relevant to each region to increase overall search efforts of rare lichens, to indicate habitat areas of special interest and to contribute to the global database of rare lichen population distributions

Effects of haloperidol on serum brain-derived neurotrophic factor (BDNF) levels in schizophrenic patients

BACKGROUND: Previous studies had reported that serum brain derived neurotrophic factor (BDNF) levels were decreased in chronic schizophrenic patients [Toyooka et al., 2002]. Recent evidence suggests that BDNF might be involved in antipsychotic action in the central nervous system, and some researchers have reported that prolonged treatment with haloperidol significantly down-regulates hippocampal BDNF protein level. However, it is unknown whether this antipsychotic drug has the similar effect on the peripheral system. In this study, we attempted to investigate the potential effect of haloperidol on patient’s serum BDNF level. METHODS: A case control study was performed on 22 chronic schizophrenic patients, under haloperidol treatment, and 22 normal controls, age and sex matched. BDNF level was measured by two site enzyme immunoassay (ELISA) method. No differences were found in the BDNF level between patients (41.46F10.72 ng/ml) and controls (38.41F7.55 ng/ml). CONCLUSION: Further research is under way to more fully understand the effect of drug treatment on serum BDNF levels and whether drug treatment normalizes serum BDNF levels