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Progressive neuronal death in monoaminergic nuclei and widespread accumulation of α-synuclein are neuropathological hallmarks of Parkinson's disease (PD). Given that α-synuclein may be an early mediator of the pathological cascade that ultimately leads to neurodegeneration, decreased α-synuclein synthesis will abate neurotoxicity if delivered to the key affected neurons.We used a non-viral gene therapy based on a new indatraline-conjugated antisense oligonucleotide (IND-ASO) to disrupt the α-synuclein mRNA transcription selectively in monoamine neurons of a PD-like mouse model and elderly nonhuman primates. Molecular, cell biology, histological, neurochemical and behavioral assays were performed.Intracerebroventricular and intranasal IND-ASO administration for four weeks in a mouse model with AAV-mediated wild-type human α-synuclein overexpression in dopamine neurons prevented the synthesis and accumulation of α-synuclein in the connected brain regions, improving dopamine neurotransmission. Likewise, the four-week IND-ASO treatment led to decreased levels of endogenous α-synuclein protein in the midbrain monoamine nuclei of nonhuman primates, which are affected early in PD.The inhibition of α-synuclein production in dopamine neurons and its accumulation in cortical/striatal projection areas may alleviate the early deficits of dopamine function, showing the high translational value of antisense oligonucleotides as a disease modifying therapy for PD and related synucleinopathies.Grants SAF2016-75797-R, RTC-2014-2812-1 and RTC-2015-3309-1, Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (ERDF), UE; Grant ID 9238, Michael J. Fox Foundation; and Centres for Networked Biomedical Research on Mental Health (CIBERSAM), and on Neurodegenerative Diseases (CIBERNED).

Pesticide exposure has been associated with neuropsychological and psychiatric impairments and neurodegenerative disorders. Pesticide exposure commonly causes a deficit in inhibitory control behaviours. In the present study, we investigated whether acute exposure to organophosphate (OP) chlorpyrifos (CPF) is related to long-term lack of inhibitory control; we also examined the possible neurochemical basis of this association. Lister Hooded rats were exposed to an acute dose of CPF (250mg/kg). Seven months later, we tested inhibitory control with the 5-choice serial reaction time task (5-CSRTT). We manipulated the baseline conditions of this task and also systemically pre-administered d-amphetamine, quinpirole, dizocilpine (MK-801) or ketanserin. We also analysed the post-mortem baseline levels of monoamines and amino acids in different brain regions. On the 5-CSRT task, CPF-exposed rats showed elevated perseverative responses that persisted across manipulation of baseline conditions of the task and under most of the pharmacological challenges tested. Only d-amphetamine induced a dose-dependent amelioration of the increased perseverative responses in the CPF group. The CPF group also exhibited increased levels of dopamine metabolism in the hippocampus and decreased levels of gamma-aminobutyric acid (GABA) and glutamate in the striatum compared to the vehicle group. These findings suggest that CPF induced a long-term compulsivity that was apparent in the 5-CSRT task and associated with changes in monoaminergic and amino acid brain systems of inhibitory control function. Exposure to high doses of OP should be taken into account in studies of environmental causes for neurodegenerative, neuropsychological and neuropsychiatric disorders., This work was supported by Grants from the Ministerio de Ciencia e Innovacion of Spain (PSI2009-08626), Ministerio de Sanidad y Consumo from Spain (FIS, PI09-01163) and FEDER funds.

Thymol is a monoterpene that specifically interacts with synaptic neural functions in neuronal GABA-operated Cl(-) channels. Here we explore the effects of thymol, and propofol as positive control, on t-[(35)S]butylbicyclophosphorothionate ([(35)S]TBPS) binding in primary cultures of cortical neurons. The study includes a meaningful analysis of the effect of various exposure buffers, and their correlation with GABA released from cells, chloride influx through the GABA(A) receptor and GABA transporter activity. Cell viability was also determined. Thymol and propofol inhibited the binding of [(35)S]TBPS to cells exposed to Tris-citrate-NaCl buffer whereas a biphasic effect was observed in HEPES solution. The different effects of the two buffers analysed are due to the higher capacity of Tris-citrate-NaCl buffer to induce the release of endogenous GABA facilitating the binding of [(35)S]TBPS to its recognition site at the GABA(A) receptor. Released GABA in the presence of this buffer was inhibited by the neuronal GABA transporter inhibitor SKF 100330-A. Tris-citrate-NaCl buffer also induced a chloride influx, which was reverted by picrotoxinin. TBPS binding in living cells is facilitated by GABA released from the cells, which in turn activates basal GABA(A) receptor activity. The results deepen on the allosteric mechanism of thymol as positive modulator of the GABA(A) receptor. Furthermore, we corroborate [(35)S]TBPS binding as an important test to verify the capacity of drugs to act on and recognize a site at the GABA(A) receptor.

Trabajo presentado en el 29th ECNP Congress, celebrado en Viena, Austria, del 17 al 20 de septiembre de 2016

Poster presentado en el 26th ECNP (European College of Neuropsychopharmacology) Congress, celebrado del 5 al 9 de octubre de 2013, en Barcelona (Espana)

Poster presentado en el 2013 ECNP Workshop on Neuropsychopharmacology for Young Scientists in Euope, celebrado del 7 al 10 de marzo de 2013 en Nice (Francia) Abstract publicado en: European Neuropsychopharmacology 23(Suppl. 1): S88 (2013). ISSN: 0924-977X. e-ISSN: 1873-7862. DOI: 10.1016/S0924-977X(13)70100-7

Trabajo presentado en el XII International Congress of Toxicology, celebrado en Barcelona, España, del 19 al 23 de julio de 2010, Dieldrin is a previously used pesticide that accumulates in the adipose tissue as well as in the brain of mammals. This organochlorine has convulsant activity because it blocks the GABAA receptor. However, little is known about the effects of a chronic exposure to this pollutant. We have previously reported that long-term exposure to dieldrin reduces the number of functional NMDA receptors (NMDARs) in neuronal cultures. On the other hand, estradiol increases synaptogenesis and promotes the delivery of NMDAR to the cell membrane. The aims of this study are: (i) elucidate which subunits of NMDAR are affected by dieldrin exposure and (ii) evaluate the effects of estradiol against dieldrin-induced NMDAR internalization. Long-term (6DIV) exposure to a subcitotoxic concentration (60 nM) of dieldrin caused the internalization of NR1 and NR2B, but not NR2A, subunits of NMDAR. Treatment with 1 nM (but not 10 nM) 17β-estradiol (E2) for 2DIV rescued dieldrin-induced decrease of NR1 and NR2B on the cell membrane but not their internalization, suggesting different mechanisms of action between the two compounds regarding NMDAR trafficking. E2 also restored NMDAR function, as measured by NMDA-induced [Ca2+]i increase. Furthermore, prolonged exposure to a higher concentration (200 nM) of dieldrin also reduced cell surface expression of NR2A, but this effect was not prevented by E2. In addition, we showed here by immunoprecipitation on membrane extraction that PSD-95 is highly physically associated with NR2A-containing (but not NR2B-containing) NMDARs in cortical neurons and moreover that this association is lost after prolonged exposure to 200 nM dieldrin. In the present study, we confirmed that the permanent blockade of the GABAA receptor by this persistent pesticide triggers adaptive neuronal changes consisting on NMDAR internalization, that might explain the learning and cognitive deficits observed in animals after chronic treatment with dieldrin. In addition, estradiol may exert beneficial effects against dieldrin-induced neurotoxicity., Supported by FIS PI061212.