0-TESTO COMPLETO.pdf - Fondazione Santa Lucia

Sezione III: Attività per progetti
Alternation Test, Morris Water Maze in standard and modified protocols) and
emotional (Porsolt’s Test) performances. The expectations are that more severe
HPA form shows more severe and general behavioural deficits, in agreement
with previous results [Cabib et al. 2003], whereas more mild forms of HPA
induce more selective cognitive deficits, characterized by deficiencies in frontal
cognitive functions. In fact, frontal/executive skills, (working memory, abstract
reasoning, problem solving, planning ability, sustained attention, inhibitory
control, mental flexibility), i.e. the functions associated with the pFC, appear to
be extremely sensible to also mildly high PHE levels [Diamond et al. 1997; Huijbregts
et al. 2002; Leuzzi et al. 2004; Smith et al. 2000; White et al. 2002]. So,
mild HPA and mild PKU mice could be characterized by more specific deficits
on Spontaneous Alternation Test and modified Morris Water Maze.
For neurochemical phenotyping, direct evaluation of fronto-cortical
aminergic neurotransmission will be evaluated by technique of in vivo intracerebral
microdialysis in ENU2 treated mice during the exposure to a psychological
experience known to affect cortical neurotransmission (restraint
stress). Moreover, tissue levels of 5-HT, DA, NE and theirs metabolites will be
analyzed in different brain areas to have a general view of brain aminergic
metabolism in different forms of HPA. It is hypothesized here that different
concentrations of blood PHE interfere differently with cognitive functions.
Preliminary results showed complete dependence of serotoninergic cortical
synthesis on blood PHE levels, offering support to role of 5-HT in HPAdependent
prefrontal cortical dysfunctions. Thus, mild HPA, mild PKU and
classic PKU mice will be temporary (one weeks) exposed to 5-HTP i.p. treatment,
and effects on behavioural and neurochemical profiles will be investigate.
We expect that 5-HTP treatment improves cognitive performances in
mild HPA mice, allowing recover of frontal cognitive functions.
PRELIMINARY RESULTS
1. ENU2 mice show alterations of dendrite and spine morphology
in medial pFC neurons
Deficits of brain amine levels in ENU2 pups, observed when pups of the
healthy background showed maximum amine peak increases, could represent
a major source of the pathologic alteration of axons, dendrites and synapses
remarked in the brain of untreated PKU patients [Bauman et al. 1982; Huttenlocher
2000; Kornguth al. 1992].
Brains of adult wild-type and ENU2 mice were dissected and impregnated
using a standard Golgi Cox solution, immersed in the GolgiCox solution
at room temperature for 6 days, transferred to a sucrose solution (30%) for 5
days and then sectioned coronally (150 mm) using a vibratome. Sections were
mounted on gelatinized slides, stained according to the Gibb and Kolb (1998)
method and covered with Permount.
Morphological characteristics of medial pFC neurons in ENU2 and wildtype
mice were examined. Six neurons per animal were considered in each
analysis The length and the number of branch nodes of the dendritic trees
were quantified tracing the entire apical and three basal dendrites. On each
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