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Le stratiote faux-aloès (Stratiotes aloides) est une plante aquatique d’eau douce vivace de la famille des Hydrocharitacées, qui forme durant l’été d’épais tapis flottants sur la surface de l’eau. Au Canada, il est considéré comme une espèce exotique envahissante. Nous rapportons ici le cas d’un étang artificiel dans la région de l’Estrie, dans le sud du Québec, qui a été envahi par cette plante. En examinant des photographies d’archives, nous avons pu confirmer la présence d’un spécimen de stratiote dans l’étang en 2013 et documenter sa propagation jusqu’en 2019, alors que l’étang était entièrement recouvert par cette plante. Ces observations ajoutent une nouvelle mention de la présence du stratiote faux-aloès au Québec et suggèrent que cette plante a un fort potentiel de propagation. Elles montrent aussi la nécessité de prévenir son introduction, de surveiller la progression des populations déjà établies et éventuellement de mettre en place des méthodes de réduction des effectifs ou d’éradication., Stratiotes aloides, or water soldier, is an aquatic freshwater perennial plant in the family Hydrocharitaceae that forms dense floating mats during summer. It is an invasive non-native species in Canada. This article documents the case of an artificial pond in the Eastern Townships region of southern Québec that rapidly became densely colonized by this species. By examining photographs, it was possible to confirm the presence of one specimen in 2013 and to document its spread until 2019, when the pond was entirely covered. These observations add a new mention of the presence of water soldier in Québec and suggest that this plant can spread quickly. They also show the need to prevent introductions, to monitor the progress of already established populations, and to possibly implement methods to reduce or eradicate the species.

The growing transportation of petroleum products pose a significant risk of marine diesel or diluted bitumen (dilbit) spills at sea. Despite the economic importance of the American lobster, there have been few studies assessing the impact study of such a spill on their population. In the lobster industry, lobster quality is monitored according to the Brix index of hemolymph. In our research, the effectiveness of three other biomarkers operative in the industry was assessed in hemolymph during contamination (over 96 h) by marine diesel and dilbit (Cold Lake Blend; CLB), as well as in the subsequent recovery period, according to two temperature cycles. At the end of the experiment, chemical and tainting assays were performed. Our results demonstrate that, among the four tested biomarkers, lysosomal stability and ethoxyresorufin O-deethylase (EROD) induction exhibit higher sensitivity. Increasing the temperature did not shorten the recovery period. Viability cellular impacts were greater in lobsters exposed to dilbit than that in those exposed to marine diesel. Marine diesel exposure appears to be more problematic for the lobster fishery, as the cooked lobster meat still presented a hydrocarbon odor even after 3 months of live holding. Finally, the high PAH concentrations measured in lobster eggs suggest potential adverse transgenerational effects of marine diesel exposure.

Bivalve aquaculture is an important component of the economy in eastern Canada. Because of current social, environmental, economic, and resource constraints, offshore mussel cultivation seems to be a promising strategy. With the objective of optimizing farming strategies that support the sustainability and development of the mussel industry at a microgeographic scale, we evaluated, after a traditional two year production cycle, the commercial performance of spat from several mussel (Mytilus edulis) stocks originating from sites separated by less than 65 km and cultivated at two different grow-out sites (shallow lagoon and offshore waters). The spatiotemporal variation in spat performance was studied through a multiyear in situ &ldquo, stock-site&rdquo, spat transfer design. The spat supply originating from the Bassin du Havre-Aubert lagoon systematically exhibited a larger size at sleeving time when compared to other stocks, and a better productivity level when harvested. Nevertheless, an alternative strategy would be to collect spat from the Havre-aux-Maisons lagoon, mostly because of the important commercial volumes of spat that can be collected there. Commercial performance (net income) was three times higher in the deep offshore grow-out site than in the shallow lagoon site. This better productivity in the open sea confirms the highly valuable strategy of offshore mussel farming in this area, where it was hypothesized that the less stressful environmental conditions positively influence reproduction, survival, and growth trends.

The indusium griseum (IG) and anterior hippocampal continuation (AHC) are longitudinal and continuous structures that consist of two narrow strips of gray matter overlying the rostrocaudal length of the corpus callosum, extending rostrally to the genu of the corpus callosum and ventrally to the rostrum. The present study aimed to characterize the phenotype of neuronal innervations to the IG-AHC and their intra-structural topographic organization. Using immunohistochemistry, we found nerve fibers expressing choline acetyltransferase, tyrosine hydroxylase, dopamine-β-hydroxylase, the serotonin reuptake transporter as well as glutamic acid decarboxylase-67 and parvalbumin. These suggest that the IG and AHC are innervated by acetylcholine, dopamine, noradrenaline, 5-hydroxytryptamine and GABA neurons. More importantly, all these fibers display a topographic laminar distribution in both brain areas. The presence of varicosities along the nerve fibers suggests that these neurotransmitters are released extracellullarly to exert a physiological action. Finally, the structural similarities with the dentate gyrus support the idea that the IG and AHC are anatomically associated, if not continuous, with this area and may represent in mammals a vestige of the hippocampus.

Depletion of cholinergic interneurons in the ventral striatum (nucleus accumbens or N.Acc.) in adult rats increases the locomotor activating effects of amphetamine. It also impairs sensorimotor gating processes, an effect reversed by the antipsychotic haloperidol. These behavioral effects are suggestive of pronounced hyper-responsiveness of the mesolimbic dopamine (DA) projection to the N.Acc. However, it is unclear whether local cholinergic depletion results predominantly in exaggerated presynaptic DA release or a postsynaptic upregulation of DAergic function. The purpose of the present study is to test the former possibility by employing in vivo voltammetry to examine changes in the levels of extracellular DA within the N.Acc. in response to either mild tail pinch stress or amphetamine administration. While both cholinergic-lesioned and control rats showed reliable stress-induced increases in extracellular DA on two consecutive test days, those in the lesioned rats were significantly less pronounced. In response to amphetamine, a separate cohort of lesioned rats also exhibited smaller increases in extracellular DA release than controls, despite showing greater locomotor activity. Moreover, the increased behavioral response to amphetamine in lesioned rats coincided temporally with decreasing levels of DA in the N.Acc. The results confirm that cholinergic depletion within the N.Acc. suppresses presynaptic DA release and suggest that lesion-induced behavioral effects are more likely due to postsynaptic DA receptor upregulation. The results are also discussed in the context of schizophrenia, where post mortem studies have revealed a selective loss of cholinergic interneurons within the ventral striatum.

Handedness in humans and paw preference (PP) in rodents have been associated with neural and physiological correlates, which frequently appear to be sex-specific. The present study examines sex differences in the effects of differential PP on post mortem measures of regional monoamine activity in adult Long-Evans rats. The effects of PP on neuroendocrine function were also assessed by measuring plasma adrenocorticotropic hormone (ACTH) in response to a 30-min restraint stress. Most rats showed strong individual PP. Males (n=27) and females (n=26) did not differ in the direction or strength of their PP with nearly equal numbers of left and right-pawed rats. However, many Sex×PP interactions were noted in regional neurochemical measures, and most effects of PP were bilateral in nature and sex-specific. In males, Left PP (relative to Right PP) was associated with reduced striatal dopamine (DA) levels and amygdala DA metabolism bilaterally. In females, Left PP was associated with a bilateral upregulation of DAergic metabolism in both prefrontal cortex and nucleus accumbens, increased amygdala serotonin metabolism, and a (right) unilateral increase in amygdala DA. As in previous studies, some correlations were also noted between PP and asymmetrical or unilateral monoamine measures. As well, rats with strong PP, independent of direction or sex, had lower basal ACTH and more robust stress responses than rats with weak PP, suggesting a possible adaptive advantage to strong lateralization. Overall, sex differences were found only regarding effects of the direction of PP, not its magnitude. The findings suggest that the direction of PP affects distinct bilateral networks of structures sex-dependently. Such fundamental influences of PP on functional brain organization have implications for a wide array of processes under monoaminergic modulation in these brain regions, and may further our understanding of the numerous human examples of gender and handedness interactions across several modalities.

Birth complications involving reduced oxygen to the fetus pose risks for neurodevelopmental disorders like schizophrenia and ADHD, which involve central dopamine (DA) dysfunction and also show gender differences in incidence or severity. Here, we examine possible sex differences in the long-term consequences of perinatal anoxia in the rat, on central DA systems and DA-mediated behaviour. As adults, sensorimotor gating (prepulse inhibition, PPI) was differentially affected by anoxia in males and females, tending to be impaired only in males. Apomorphine-induced suppression of PPI was especially pronounced in males. Anoxia caused increases in amygdala DA levels in both sexes. However, sex-specific changes in DA and metabolite levels in prefrontal cortex and nucleus accumbens were found, suggesting a possible basis for some of the observed gender biases in certain neurodevelopmental disorders, sensitive to birth hypoxia.

A delicate balance between dopaminergic and cholinergic activity in the ventral striatum or nucleus accumbens (N.Acc) appears to be important for optimal performance of a wide range of behaviours. While functional interactions between these systems are complex, some data suggest that acetylcholine in the N.Acc. may dampen the effects of excessive dopamine (DA) release. We proposed that a reduction in the density of cholinergic interneurons in the N.Acc would result in behavioural alterations suggestive of a hyper-responsiveness of the N.Acc DA system. The present study aimed to produce a sustainable depletion of cholinergic neurons in the N.Acc in the rat and study the effects of such lesions on DA-dependent behaviour. A novel saporin immunotoxin targeting choline acetyltransferase was microinjected bilaterally into the N.Acc of adult rats. We confirmed histologically that two weeks post-injection, animals show a local, selective depletion of cholinergic interneurons (mean cell loss of 44%). Cholinergic-depleted rats showed a marked increase in the locomotor activating effects of amphetamine. In addition, such lesions induced a disruption of sensorimotor gating processes, reflected in a reduction in the prepulse inhibition of the acoustic startle response, which was reversed by haloperidol. These data are suggestive of pronounced hyper-responsiveness of the meso-accumbens DA system which may be of relevance to the pathophysiology of schizophrenia, a condition where selective reduction in the number of ventral striatal cholinergic neurons has been demonstrated.

Mobile robots (i.e., robots capable of translational movements) can be designed to become interesting tools for child development studies and pediatric rehabilitation. In this article, the authors present two of their projects that involve mobile robots interacting with children: One is a spherical robot deployed in a variety of contexts, and the other is mobile robots used as pedagogical tools for children with pervasive developmental disorders. Locomotion capability appears to be key in creating meaningful and sustained interactions with children: Intentional and purposeful motion is an implicit appealing factor in obtaining children's attention and engaging them in interaction and learning. Both of these projects started with robotic objectives but are revealed to be rich sources of interdisciplinary collaborations in the field of assistive technology. This article presents perspectives on how mobile robots can be designed to address the requirements of child-robot interactions and studies. The authors also argue that mobile robot technology can be a useful tool in rehabilitation engineering, reaching its full potential through strong collaborations between roboticists and pediatric specialists.

By its projections to the primary visual and the prefrontal cortices, the basal forebrain cholinergic system is involved in cognitive processing of sensory stimuli. It has been suggested that visual stimulus-induced cholinergic activation of the visual cortex may exert a permissive role on thalamocortical inputs. However, it is not known if visual stimulation elicits cholinergic activation of high-order brain areas in the absence of attentional need. In the present study, we measured the effects of patterned visual stimulation (horizontal grating) on the release of acetylcholine with dual-probe in vivo microdialysis in the visual and the prefrontal cortices of anesthetized rats. We also used retrograde tracing to determine the anatomical relationships of cholinergic neurons with neurons of the visual system and the prefrontal cortex. Finally, we evaluated a functional correlate of this stimulation, namely c-fos immunolabeling. Patterned visual stimulation elicited significant increases in acetylcholine release in the visual cortex, accompanied by an increased number of c-fos immunoreactive neurons in this brain area. In contrast, in the prefrontal cortex, neither the level of acetylcholine release nor the number of c-fos immunoreactive neurons was significantly changed because of the stimulation. Cholinergic basal forebrain neurons projecting to the visual or the prefrontal cortices were both localized within the horizontal limb of the diagonal band of Broca but were not immunoreactive for c-fos during visual stimulation. No parts of the visual system were found to directly project to these basal forebrain neurons. These results suggest the differential involvement of cholinergic projections in the integration of sensory stimuli, depending on the level of activity of the targeted cortical area.

Excitotoxic neonatal ventral hippocampus (NVH) lesions in rats result in characteristic post-pubertal hyper-responsiveness to stress and cognitive abnormalities analogous to those described in schizophrenia and suggestive of alterations in dopamine (DA) neurotransmission. Converging lines of evidence also point to dysfunctions in the cortical cholinergic system in neuropsychiatric disorders. In previous studies, we observed alterations in dopaminergic modulation of acetylcholine (Ach) release in the prefrontal cortex (PFC) in post-pubertal NVH-lesioned rats. These two neurotransmitter systems are involved in the stress response as PFC release of DA and Ach is enhanced in response to some stressful stimuli. As adult NVH-lesioned rats are behaviorally more reactive to stress, we investigated the effects of NVH lesions on tail-pinch stress-induced Ach and DA release in the PFC. Using in vivo microdialysis, we observed that tail-pinch stress resulted in significantly greater increases in prefrontal cortical Ach release in post-pubertal NVH-lesioned rats (220% baseline) compared with sham-operated controls (135% baseline). Systemic administration of the D1-like receptor antagonist SCH 23390 (0.5 mg/kg i.p.) or the D2-like receptor antagonist haloperidol (0.2 mg/kg i.p.), as well as intra-PFC administration of the D2-like antagonist sulpiride (100 µm), reduced stress-induced Ach release in PFC of adult NVH-lesioned rats. By contrast, intra-PFC administration of SCH 23390 (100 µm) failed to affect stress-induced Ach release in PFC of NVH-lesioned rats. Interestingly, using in vivo voltammetry, stress-induced stimulation of PFC DA release was found to be attenuated in adult NVH-lesioned rats. Taken together, these data suggest developmentally specific reorganization of prefrontal cortical cholinergic innervation notably regarding its regulation by DA neurotransmission.

The electrocatalytic hydrogenation (ECH) of phenol was carried out in aqueous media with a commercial Pd/Al2O3 (5% w/w) catalyst. A porous matrix of reticulated vitreous carbon (RVC) was used to study the porosity – stirring speed coupling (PSSC) effect on the phenol hydrogenation to form cyclohexanone and cyclohexanol. In accordance with the PSSC, the electrode can act as a fluidized bed electrode or as an agglomerated electrode. Fluidized bed electrodes develop for low porosity matrices (10–30 ppi, ppi = pores per inch) at high stirring speeds (>600 rpm), while agglomerated electrodes are obtained for high porosity matrices (60–100 ppi) with moderate stirring speeds under cathodic polarization. The distribution of the volume fraction of the particles and the agglomeration of the particles have been simulated by computational fluid dynamic (CFD) methods with FLUENT software. For the agglomerated electrode, the numerical simulations demonstrate the beneficial contribution of the cathodic polarization to the agglomeration process. However, at 650 rpm, for the fluidized bed electrode, the volume fraction of the particles in the RVC does not account for the distinction in the ECH efficiency between the 30 ppi matrix and the 100 ppi matrix. For a given amount of Pd/Al2O3 catalyst, it is observed that the ECH rates depend on the PSSC and increase in the following order: 100/650 < 30/650 < 100/200. Key words: electrocatalytic hydrogenation (ECH), CFD, fluid mechanics, porous media, powder, porosity – stirring speed coupling (PSSC), reticulated vitreous carbon (RVC).

Excitotoxic lesion of the ventral hippocampus in neonatal rats is a putative animal model of schizophrenia with characteristic developmental abnormalities in dopaminergic neurotransmission and prefrontal cortical functions. Converging evidence also points to the involvement of the central cholinergic system in neuropsychiatric disorders. These two neurotransmitter systems are interlinked in the prefrontal cortex (PFC) where dopamine stimulates acetylcholine (ACh) release. In the present study, we investigated the role of dopamine in the developmental regulation of prefrontal cortical ACh release and the expression of nicotinic and muscarinic receptors in pre- and post-pubertal rats with neonatal ibotenic acid-induced lesions of the ventral hippocampus (NVH). In vivo microdialysis in the PFC revealed that systemic injections of the D(1)-like receptor agonist (+/-)-6-chloro-7,8-dihydroxy-1-phenyl2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF 81297) (2.5 and 5.0 mg/kg i.p.) caused significantly higher ACh release in post-pubertal NVH-lesioned animals (250 and 300% baseline for 2.5 and 5.0 mg/kg, respectively) compared with post-pubertal shams (150 and 220% baseline for 2.5 and 5.0 mg/kg, respectively). Most interestingly, while prefrontal cortical perfusion of SKF 81297 (100 and 250 microM) had no significant effect on ACh release in post-pubertal sham-operated animals, it significantly stimulated ACh release to approximately 250% baseline at both doses in post-pubertal NVH-lesioned animals. Receptor autoradiography demonstrated a significant and selective increase in M(1)-like receptor binding sites in the infralimbic area of the PFC in the post-pubertal NVH-lesioned animals. For all experiments, significant differences between sham and NVH-lesioned animals were observed only in post-pubertal rats. These results suggest a developmentally specific reorganization of the prefrontal cortical cholinergic system involving D(1)-like receptors in the NVH model.

Henry's law constants were determined for cyclohexanone adsorption onto aluminium oxide – hydroxide powders by dynamic isotherm measurements using the HPLC method. The key parameters that control cyclohexanone adsorption were established. Further, it is suggested that the amount of cyclohexanone adsorbed onto aluminium oxide – hydroxide compounds (AOHC) is of paramount importance for its electrocatalytic hydrogenation in the presence of composite nickel–AOCH powders.Key words: adsorption isotherm, electrocatalytic hydrogenation (ECH), cyclohexanone, aluminum oxide – hydroxide powders.

The electrocatalytic hydrogenation (ECH) of phenol was carried out in aqueous media with catalytic powders. The catalytic powders were composed of palladium nanoaggregates deposited on various substrates such as Al2O3, BaSO4, and BaCO3. Composite powders are trapped (upon stirring) into a reticulated vitreous carbon (RVC) matrix, allowing a rapid in situ build-up of the electrode and alleviating the use of a binder, since the latter may have a detrimental effect on the ECH. For a given amount of noble metal (5% palladium by weight), it is observed that the ECH of phenol to cyclohexanol increases in the following order: Pd/BaCO3< Pd/BaSO4< Pd/Al2O3. It is deduced that the ECH rate is largely dependent on the adsorption of organic molecules on the nonmetallic substrate, and a model is considered to explain such a behavior. The ECH of phenol is also feasible at a reasonable rate with composite Pd/Al2O3(0.25% Pd by weight) powders fabricated by physical vapor deposition because the peripheral distribution of Pd nanoaggregates is favorable towards the ECH.Key words: electrocatalytic hydrogenation (ECH) of phenol, reticulated vitreous carbon (RVC), alumina-based catalyst, agglomeration process, adlineation point, adsorption.

The electrocatalytic hydrogenation of cyclohexanone has been investigated with catalytic powder particles made of metal nanoaggregates deposited on a nonconductive material such as activated carbon and alumina. The catalytic powder particles were suspended in the solution under vigorous stirring conditions. The brief contact of the powder particles with a porous carbon cathode was sufficient to form adsorbed hydrogen on the metallic nanoaggregates through water electrolysis and initiate the electrohydrogenation process. It is demonstrated that the key parameters of the electrohydrogenation process are both the nature of the metallic nanoaggregates and the nature of the non-conductive material. The hydrodynamics of the solution under vigorous stirring conditions have also been studied for the particular cell used in the present study.

A study of the electrocatalytic hydrogenation (ECH) process of pyrrole and different alkyl pyrrole-2-carboxylates is presented. Once hydrogenated, the alkyl pyrrole-2-carboxylate becomes an ester of proline, an important natural amino acid. The process is chemoselective to the pyrrole ring. Ryanodine is a natural ryanoid known to be biologically active. The tetrahydroryanodine derivative thus obtained may now represent a molecule of high biological interest. The hydrogenation of ryanodine is possible with electrocatalytic and catalytic processes. In both cases the reaction is not diastereoselective.Key words: electrocatalytic hydrogenation, proline esters, ryanodine, tetrahydroryanodine.

The mesocortical dopamine (DA) system of the rat plays an important role in prefrontal cortex (PFC) regulation of stress and emotion and exhibits functional hemispheric asymmetry for such processing. Since few studies examine sex differences in this context, we compared the effects of left vs. right unilateral PFC DA depletion in males and females in several behavioral situations associated with anxiety or aversion. Adult rats received unilateral injections of 6-hydroxydopamine (6-OHDA) or vehicle in the ventromedial (vm) PFC. Behavioral tests included a predator odor burying test, elevated plus maze and sucrose consumption with simple taste aversion. Tissue analysis confirmed that vmPFCs injected with 6-OHDA were depleted of DA (75-85%) compared to controls. Burying behavior and sucrose consumption were affected only by left lesions, similarly in both sexes. However, risk assessment behaviors were affected by right lesions in opposite directions in males and females. Behaviors modified preferentially by the left cortex thus showed less evidence of sex differences than those modulated by the right. While mesocortical DA depletion effects are lateralized, the nature of these effects can vary with sex and specific behavior. Such findings may be clinically significant, given the large gender differences in the incidence of mood and anxiety disorders, which also show many lateralized prefrontal abnormalities.

The electrocatalytic hydrogenolysis of pentachlorophenol (PCP) was carried out under galvanostatic control, in an aqueous 1 M NaOH solution in which PCP is fully soluble, and on particles of palladium or rhodium supported on alumina (Pd(5%)/Al2O3 or Rh(5%)/Al2O3) and entrapped in a reticulated vitreous carbon (RVC) electrode. On Pd/Al2O3 and at 75 °C, the conversion was complete (>99%) after 16 mol of electrons per mol of substrate (16 F mol-1) were consumed, and phenol was the sole product formed in 98% yield (61% current efficiency). On Rh/Al2O3 and 25 °C, 100% conversion was reached after 24 F mol-1, and cyclohexanol was obtained in 98% yield with some 2% of cyclohexanone (62% current efficiency). The ease of electrocatalytic hyrogenolysis was found to increase in the following order: PCP < 2,6-dichlorophenol < 4-chlorophenol.

Purpose: Patient advisors are peer volunteers who have already been through a digit replantation. They are fully trained and viewed as full-fledged members of the care team. This proof-of-concept study was aimed at describing a model of care that brings patient advisors directly to the patient’s bedside. In this model, the patients’ perception of disability, the adherence to the rehabilitation process, and overall satisfaction were reported. Methods: A prospective pilot study was conducted from July 2014 to June 2015. All patients admitted to a center of expertise were offered the option to interact with patient advisor at bedside. Meetings were generally brief (15-30 minutes) and were proposed on the fifth day postsurgery as well as 8 and 16 weeks following surgery. The Disabilities of the Arm, Shoulder and Hand (DASH; 30 items scored 1-5) questionnaire was completed at 8 and 16 weeks follow-up as a measure of self-rated upper extremity disability and symptoms. All patients who had at least 1 interaction with a patient advisor were interviewed by telephone after study completion. The purpose of the interviews was to understand their expectations, the contribution of the patient advisor in their own care, and any possible reluctance or difficulty encountered (particularly when interactions were conducted via videoconferencing). Adherence to the rehabilitation process was also recorded and later compared to an estimate of 35% adherence generated from our Institution. Results: Based on an average of 9 patients, the DASH score completed at week 16 (27.6) showed a decrease of 33.8% when compared with that of week 8 (41.7). Adherence to treatment plan was respected in 55% of patients with patient advisor’s interaction, which was higher than estimations. Several key roles of the patient advisors emerged from the 18 interviews conducted on patients. Patient advisor is perceived as a care team member who will listen and support the patient, simplify the information conveyed by the care team, and finally break the patients’ loneliness, increasing their motivation toward the rehabilitation process. Conclusion: This study underlines the potential of patient advisors to improve the perception of disability and the adherence to the rehabilitation process in patients who have undergone digits replantation. Measurements of hand strength, range of motion, and sensibility as well as self-reported pain, posttraumatic stress disorder, and self-esteem were also performed; analyses are ongoing at present time. Further researches are required before widespread dissemination of the usefulness of patient advisors.

In rats, selective depletion of the cholinergic interneurons in the ventral striatum (nucleus accumbens or N.Acc.) results in heightened behavioural sensitivity to amphetamine and impaired sensorimotor gating processes, suggesting a hyper-responsiveness to dopamine (DA) activity in the N.Acc. We hypothesized that local cholinergic depletion may also trigger distal functional alterations, particularly in prefrontal cortex (PFC). Adult male Sprague-Dawley rats were injected bilaterally in the N.Acc. with an immunotoxin targeting choline acetyltransferase. Two weeks later, cognitive function was assessed using the delayed alternation paradigm in the T-maze. The rats were then implanted with voltammetric recording electrodes in the ventromedial PFC to measure in vivo extracellular DA release in response to mild tail pinch stress. The PFC was also examined for density of tyrosine hydroxylase (TH)-labelled varicosities. In another cohort of control and lesioned rats, we measured post mortem tissue content of DA. Depletion of cholinergic neurons (restricted to N.Acc.) significantly impaired delayed alternation performance across delay intervals. While (basal) post mortem indices of PFC DA function were unaffected by N.Acc. lesions, in vivo mesocortical DA activation was markedly reduced; this deficit correlated significantly with cognitive impairments. TH-labelled varicosities however, were unaffected in cortical layer V relative to controls. These data suggest that selective depletion of cholinergic interneurons in N.Acc. triggers widespread functional impairments in mesocorticolimbic DA function and cognition. The possible relevance of these findings is also discussed in relation to schizophrenia, where reduced density of cholinergic neurons in ventral striatum has been reported.

Acute myocardial infarction (MI) is followed, within a few hours, by neuronal loss in the central nervous system (CNS), including the limbic system, the hypothalamus, and the brainstem. Sleep before and after MI was investigated in the first experiment. In a parallel experiment, 2 weeks after MI, we quantified brainstem cholinergic neurons known to control paradoxical sleep (PS).Data were obtained from 28 adult male Sprague-Dawley rats weighing 350-375 g and maintained under a 12-12 light-dark cycle in 2 experiments on 16 and 12 rats, respectively. The 16 animals in the first experiment were implanted with chronic electroencephalographic (EEG) and electromyographic (EMG) electrodes. A week after surgery, these animals were habituated for 2 days to the recording equipment, and baseline sleep was charted for 24 h. The next morning, MI was induced in 8 rats by occluding the left anterior descending coronary artery for 40 min. The remaining 8 rats served as sham-operated controls. Sleep was recorded again 2 weeks after MI. The number of choline acetyltransferase (ChAT)-positive neurons was counted in the second, parallel experiment on 6 MI and 6 sham rats. Compared to the sham controls, MI rats displayed longer latency to sleep onset, shorter latency to paradoxical sleep (PS), and curtailed PS duration. The number of ChAT-positive neurons in the pedunculopontine tegmentum (PPT) area of MI rats was significantly decreased compared to the sham controls, while the number of laterodorsal tegmentum (LDT) cholinergic neurons was not different.Acute MI is accompanied, within 2 weeks, by PS-specific insomnia that can be explained, at least partly, by a specific loss of cholinergic neurons in an area known to control PS.

Excitotoxic neonatal ventral hippocampal (NVH) lesion in rats is considered as a putative animal model of schizophrenia as lesioned animals show characteristic post-pubertal emergence of neurochemical and behavioral abnormalities analogous to some of those seen in this disease. Converging evidence points to the involvement of central cholinergic system in this neuropsychiatric disorder, and our previous studies have suggested that cholinergic neurotransmission may be altered in post-pubertal NVH lesioned rats. We investigated here muscarinic receptor reactivity in NVH lesioned animals by measuring the effects of the muscarinic receptor agonist oxotremorine on physiological responses known to be modulated by these receptors such as body temperature, salivation, tremor, pain, and prepulse inhibition of the acoustic startle (PPI). Quantitative receptor autoradiography revealed that post-pubertal NVH lesioned animals display increased levels of [3H]pirenzepine/M1-like and [3H]AFDX-384/M2-like receptor binding sites in the striatum, nucleus accumbens, and in subareas of the dorsal hippocampus. Moreover, in response to the systemic administration of oxotremorine (0.25 mg/kg), post-pubertal NVH lesioned rats exhibited increases in salivation and tremor, and a greater reduction in body temperature compared to sham control animals. Increases in the hot-plate latency were also observed suggesting enhanced antinociceptive effects of oxotremorine in post-pubertal NVH lesioned animals. Finally, oxotremorine (0.1 and 0.25 mg/kg) disrupted PPI in post-pubertal sham control rats while the muscarinic receptor antagonist biperiden (0.5 and 1.0 mg/kg) normalized this behavior in NVH lesioned rats. Taken together, these findings reveal that post-pubertal NVH lesioned rats display enhanced muscarinic receptor responsiveness, which may relate to some behavioral abnormalities reported in this animal model.

Approximately two years after the introduction of highly active antiretroviral therapy for the treatment of HIV infection, body shape changes and metabolic abnormalities were increasingly observed. Initially, these were ascribed to protease inhibitors, but it is now clear that nucleoside reverse transcriptase inhibitors also contribute to lipodystrophy syndrome. The syndrome groups together clinical conditions describing changes in body fat distribution that include lipoatrophy, lipoaccumulation or both. However, there does not appear to be a direct link between lipoatrophy and lipoaccumulation that would support a single mechanism for the redistribution of body fat. Currently, there is no clear definition of lipodystrophy, which explains the difficulty in determining its prevalence and etiology. There are no current guidelines for the treatment of fat distribution abnormalities that occur in the absence of other metabolic complications. The present article reviews the current state of knowledge of the definition, symptoms, risk factors, pathogenesis, diagnosis and treatment of the morphological changes associated with lipodystrophy syndrome.

Activation of the dopamine D1-like receptor stimulates acetylcholine (ACh) release in the hippocampus, apparently through the molecularly defined d5 receptor. In the present study, we used a transgenic mouse completely deprived of functional d5 receptor (d5-/-) to confirm the role and elucidate the possible function of the d5 receptor subtype on hippocampal cholinergic neurotransmission. ACh release was measured using in vivo microdialysis in the mouse dorsal hippocampus of 4 months old homozygous (d5-/-), heterozygous (d5+/-), and the wild-type (d5+/+) littermates. Using the no net flux technique, a significant reduction in basal hippocampal ACh level was found in the d5-/- compared to d5+/- and d5+/+ mice. Moreover, the administration of SKF 38393, a D1-like receptor agonist, systemically (2.0 and 10.0 mg/kg ip), or locally through the dialysis probe (10 and 50 microM), produced a dose-dependent enhancement of ACh release in the d5+/+, a moderate stimulation in the d5+/- but had no effect in the d5-/- mice. Quantitative receptor autoradiography revealed significant increases in M1-like but not in M2-like muscarinic receptor binding sites in the hippocampal formation. These results confirm and extend the role of the d5 receptor in the modulation of hippocampal ACh release and provide evidence for long-term alteration of hippocampal cholinergic neurotransmission resulting from the absence of the d5 receptors including chronically reduced ACh release and change in M1-like receptor levels.

The neuropeptide galanin is an inhibitory modulator of hippocampal acetylcholine (ACh) release and cognitive functions. Anatomical evidence demonstrated some differences between the dorsal and ventral hippocampi notably in the expression of galanin receptor subtypes, and the neuronal population on which galanin-like immunoreactivity is expressed. This is suggestive of a differential role for this peptide in these two areas of the hippocampal formation. Using in vivo microdialysis, we investigated the role of galanin on ACh release in the dorsal and ventral hippocampi. Two models were studied: galanin-administered rats and transgenic mice over-expressing galanin (GAL-tg). In rats, galanin (2.0 and 10.0 microM) infused locally through the dialysis probe induced a significant decrease in ACh release in the ventral hippocampus, confirming previous findings, while no effect was seen in the dorsal hippocampus. Using the no net flux method, a significant reduction in ACh levels was noted only in the ventral hippocampus of GAL-tg compared to wild-type littermates. These results suggest that excess endogenous galanin can suppress basal ACh release, with anatomical specificity, to the ventral hippocampus. These results are of interest in the context of galanin receptor subtypes in the dorsal and ventral hippocampus, and the differential alterations of hippocampal subregions in neurological diseases such as Alzheimer's dementia.