Anna Maria Garau

Maternal separation attenuates the effect of adolescent social isolation on HPA axis responsiveness in adult rats

Adverse early life experiences that occur during childhood and adolescence can have negative impacts on behavior later in life. The main goal of our work was to assess how the association between stressful experiences during neonatal and adolescent periods may influence stress responsiveness and brain plasticity in adult rats. Stressful experiences included maternal separation and social isolation at weaning. Three hours of separation from the pups (3-14 PND) significantly increased frequencies of maternal arched-back nursing and licking-grooming across the first two weeks postpartum. Separation also induced a long-lasting increase in dams blood levels of corticosterone. Maternal separation did not modify brain and plasma allopregnanolone and corticosterone levels in adult offspring, but they demonstrate partial recovery from the reduction induced by social isolation during adolescence. Moreover, the enhancement of corticosterone and allopregnanolone levels induced by foot shock stress in socially isolated animals that were subjected to maternal separation was markedly reduced with respect to that observed in animals that were just socially isolated. All experimental groups showed a significant reduction of BDNF and Arc protein expression in the hippocampus. However, the reduction of BDNF observed in animals that were maternally separated and subjected to social isolation was less significantly pronounced than in animals that were just socially isolated. The results sustained the mismatch hypothesis stating that aversive experiences early in life trigger adaptive processes, thereby rendering an individual to be better adapted to aversive challenges later in life.

Altered stress responsiveness and hypothalamic-pituitary-adrenal axis function in male rat offspring of socially isolated parents

Social isolation in male rats at weaning results in reduced basal levels of the neuroactive steroid 3α,5α‐tetrahydroprogesterone (3α,5α‐TH PROG) in the brain and plasma as well as increased anxiety‐like behavior. We now show that socially isolated female rats also manifest a reduced basal cerebrocortical concentration of 3α,5α‐TH PROG as well as an anxiety‐like profile in the elevated plus‐maze and Vogel conflict tests compared with group‐housed controls. In contrast, despite the fact that they were raised under normal conditions, adult male offspring of male and female rats subjected to social isolation before mating exhibited an increased basal cerebrocortical level of 3α,5α‐TH PROG but no difference in emotional reactivity compared with the offspring of group‐housed parents. These animals also showed an increased basal activity of the hypothalamic‐pituitary‐adrenal axis as well as reduced abundance of corticotropin‐releasing factor in the hypothalamus and of corticotropin‐releasing factor receptor type 1 in the pituitary. Moreover, negative feedback regulation of hypothalamic‐pituitary‐adrenal axis activity by glucocorticoid was enhanced in association with up‐regulation of glucocorticoid receptor expression in the hippocampus. There was also attenuation of corticosterone release induced by foot‐shock stress in the offspring of socially isolated parents. The increase in the brain concentration of 3α,5α‐TH PROG induced by acute stress was also blunted in these animals. Our results thus show that a stressful experience before mating can influence neuroendocrine signaling in the next generation.

Chlorpyrifos residues levels in fruits and vegetables after field treatment

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) was applied with three different formulations on oranges, peaches, tomatoes, wine and table grapes, and its behaviour was evaluated after field treatment. The formulations applied were emulsifiable concentrates (EC), microencapsulates (ME), and wettable granules (WG). The residues were similar in all crops studied in the EC and WG experiments, except peaches with WG treatment, the residue amount was lower than EC values. Tomatoes which were grown in greenhouse showed similar residues in all treatments just after treatment. Wine and table grapes showed different decline curves in the EC experiments ascribable to the different growing technology. Instrumental limit of determination (LOD) and limit of quantification (LOQ) for all matrices were 0.01, and 0.03 mg kg−1, respectively. Repeated treatments showed that Chlorpyrifos can accumulate leading to residue levels at the preharvest interval (PHI) over the maximum residue level (MRL), especially on oranges and peaches. Among the formulates used ME showed the higher risk of residues over the MRL at harvest.

Mineralogical, petrographic and chemical analysis of geomaterials used in the mortars of Roman Nora theatre (south Sardinia, Italy)

The composition and the origin of raw materials used in the ancient mortars and concrete of the Nora theatre (first century AD) have been analysed to define their provenance and construction technologies of the Roman period.The use of geomaterials in the binder / aggregate mixtures of the mortars vary according to their function in the different sectors (i.e., structure-wall, tribunalia vaults, wall of external niches, foundation of cavea tiers, stage inner wall) but also according to different construction phases of the theatre or the work-steps. The mortars with structural function are mainly hydraulic (e.g., concrete of vaults, jointing and foundation mortars of cavea ashlars), while the lime mortars were used mainly for plasters, and rarely as bedding mortars. As recommended by Vitruvius, in the hydraulic mortars were mainly used volcanic rocks, as coarse and fine pozzolanic aggregate (pulvis puteolanus), and quartz-feldspar sands (present as crystal-clasts with an almost constant ratio of about 2:1, respectively). The cocciopesto is anomalously rare or absent. In the mortars local dacitic volcanic rock were also used, especially in the concrete as caementia.The grey-black volcanic rocks are glasses with characteristics more near to obsidian and less to natural pozzolan normally used in the Roman period. To identify the provenance of these glasses, a geochemical comparison between the samples taken from the theatre mortars and the volcanic outcrops of some probable Sardinian source areas is made by XRF and SEM-EDS / WDS analysis.To verify the quality of the pozzolan (by its chemical reaction with the binder), the edges and inside of volcanic glasses were analysed with an SEM-EDS microprobe, while the compositional characteristics and the hydraulic degree of the binder was analysed with XRPD and TG/DSC methods, respectively.The use of this kind of pozzolanic glass, without local origins, is a novelty because it has never been found in the mortars of the archaeological site of Nora. Given the wide use of Sardinian obsidian in the Neolithic or Calcolithic periods for production of tools and instruments, some considerations about its use, origin and trade are made.

Geochemical characterisation of pozzolanic obsidian glasses used in the ancient mortars of Nora Roman theatre (Sardinia, Italy): provenance of raw materials and historical–archaeological implications

The study focused on the volcanic glass used in the production of bedding mortars and concrete of the Roman theatre (I cent. AD) of the Nora site. The volcanic glasses were frequently used as aggregate and with pozzolanic function in all hydraulic mortars of the different sectors of the building (e.g., concretes of tribunalia vaults and external niches, jointing and foundation mortars of cavea tier ashlars, brick bedding), together with mainly quartz-feldspar sands, local Oligo-Miocenic andesitic-dacitic volcanics and Palaeozoic and Tyrrhenian sedimentary rocks. These volcanic glasses show characteristics closer to obsidian than to natural pozzolan normally used in the Roman period. They have definitely not sourced locally, unlike the other components that make up the aggregate. To identify their provenance, a petrochemical comparison between several samples taken from the theatre mortars and the volcanic outcrops of some probable Sardinian source areas is made. The use of the not local pozzolanic glass is a technical innovation in the mortars of the Nora archaeological site, and considering the wide use of obsidians in the prehistoric periods for the production of tools, significant considerations about its origin, procurement and use are made.

Juvenile social isolation affects maternal care in rats: involvement of allopregnanolone

RationaleSocial isolation of rats immediately after weaning is thought to represent an animal model of anxiety-like disorders. Socially isolated virgin females showed a significant decrease in allopregnanolone levels, associated with increased anxiety-related behavior compared with group-housed rats.ObjectivesThe present study investigates whether post-weaning social isolation affects maternal behavior and assesses neuroactive steroid levels in adult female rats during pregnancy and postpartum.ResultsSocially isolated dams displayed a reduction in the frequency of arched back nursing (ABN) behavior compared to group-housed dams. In addition, both total and active nursing were lower in socially isolated dams compared to group-housed dams. Compared to virgin females, pregnancy increases allopregnanolone levels in group-housed as well as isolated dams and such increase was greater in the latter group. Compared to pregnancy levels, allopregnanolone levels decreased after delivery and this decrease was more pronounced in isolated than group-housed dams. Moreover, the fluctuations in plasma corticosterone levels that occur in late pregnancy and during lactation follow a different pattern in socially isolated vs. group-housed rats.ConclusionsThe present results show that social isolation in female rats decreases maternal behavior; this effect is associated with lower allopregnanolone concentrations at postpartum, which may account, at least in part, for the poor maternal care observed in socially isolated dams. In support of this conclusion is the finding that finasteride-treated dams, which display a decrease in plasma allopregnanolone levels, also showed a marked reduction in maternal care, suggesting that allopregnanolone may contribute to the quality of maternal care.

P.1.014 Spatial memory and expression levels of BDNF and steroid hormone receptors in the hippocampus of socially isolated offspring

Purpose: Rats deprived of social contact with other rats at a young age experience a form of prolonged stress that leads to long-lasting alteration in their behaviour profile. This chronic stress paradigm results in changes of emotional state, hormonal secretion, abnormal reactivity to environmental and pharmacological stimuli and changes in GABAA receptor plasticity and function [1,2]. Moreover, isolated rats, although showed a down-regulation of both brain-derived neurotrophic factor (BDNF) and activityregulated cytoskeletal associated protein (Arc) in the hippocampus, demonstrated an improvement in memory performances in the Morris water maze (MWM) together with an increase in the expression of BDNF and Arc in the hippocampus on both days 1 and 5 and increased plasma level of corticosterone on the 5th day of MWM training [3]. To examine possible trans-generational effects on social isolated offspring we have investigated (1) basal plasma levels of corticosterone, (2) spatial memory performance in the MWM, (3) expression levels of BDNF and Arc in the hippocampus during the 1th and 5th days of MWM. Moreover, in the hippocampus of both isolated and isolated offspring we measured the expression levels of glucocorticoid (GR) and mineralcorticoid (MR) receptors. Methods:Male Sprague-Dawley rats were used. Steroid levels were quantified in plasma by RIA. The levels of BDNF, Arc, GR and MR proteins were determined by Western Blot analysis. The measurement of spatial memory was performed trough the MWM. Data were analyzed by one or two-way ANOVA followed by Newman-Keuls post-hoc test. Results: In social isolated offspring the plasma levels of corticosterone were significantly increased by 31% (p< 0.05) vs group-housed offspring (controls). In the MWM, social isolated offspring showed a decrease in latency to reach the platform during the days of training, and a decrease of the proximity measure to the target zone during the probe trial. Moreover, although the basal levels of hippocampal BDNF and Arc did not differ significantly between the two groups of animals, we found a significant increase of BDNF expression at the 5th day of MWM in isolated offspring vs the control animals (p< 0.05). Finally, the expression of hippocampal GR was significantly augmented in both isolated and isolated offspring (+41%, p< 0.05; +42%, p< 0.05, respectively), while the expression of MR was significantly increased only in the isolated rats (+35%, p< 0.05). Conclusions: Our results suggest that a stressful condition that have been experienced by the parents in early life time influence hormonal secretion, neuronal plasticity and cognitive performances in the offspring. Thus, isolated offspring showed an improvement in learning and spatial memory in MWM vs the control animals. Likewise, high circulating levels of corticosterone with high levels of GR expression in the hippocampus may play an important role in improving the cognitive performance of these animals. These data are in agreement with the increased expression of BDNF since it is involved in various forms of hippocampal learning.