Novel Mechanisms Regulating Alcohol Seeking and Relapse: The View from Latin-America

VALENZUELA J.; PAUTASSI R.M.

San Diego

Congreso; 2018 Meeting of the Research Society on Alcoholism (RSA); 2018

Research Society on Alcoholism (RSA)

TUESDAY, JUNE 19 3:10 PM?4:40 PMSYMPOSIUM 236?239Novel Mechanisms Regulating Alcohol Seeking and Relapse: The View fromLatin-AmericaOrganizers/Chairs: C. Fernando Valenzuela and Ricardo Pautassi236FETAL PROGRAMMING OF HEIGHTENED ETHANOL PREFERENCE AND NEONATALBREATHING DISRUPTIONS: COMMON DENOMINATORS BASED ON ETHANOL-RELATEDLEARNING PROCESSESA.F. Macchione1,2, M.B. Acevedo1,2, S. Castello1,2, G. D0Aloisio1,2, F. Anunziata1,2, V. Trujillo1,2,J.C. Molina1,21Instituto de Investigacion M edica Mercedes y Mart ın Ferreyra, Friuli 2434, Cordoba-5016, Argentina and 2Facultad de Psicologıa, Universidad Nacional de Cordoba, Ciudad Universitaria, Cordoba-5000, Argentina Beyond the well known teratological effects of ethanol, preclinical studies have systematicallydemonstrated that moderate ethanol doses recruit sensory and learning capabilities of the near termfetus. When ethanol accumulates in the amniotic fluid, the unborn organism processes itschemosensory cues. Familiarization with ethanol0s sensory attributes results in later recognition andacceptance of the odor and taste of the drug. This memory is modulated by different physiologicalconsequences of the state of intoxication. Relative to this issue, a series of studies have been conducted in rats and humans. Preclinical approaches have dealt with functional learning capabilities ofthe near term fetus and during neonatal life (stages that in terms of brain synaptogenesis are analogous to the 2nd and 3rd human gestational trimesters; respectively). Brief experiences with moderate ethanol doses (0.5?2.0 g/kg) were sufficient to sensitize the developing organism to ethanol0sreinforcing effects. The studies also demonstrated an early capability of associating ethanol0s sensory cues with the reinforcing effects of the drug. The associative memory enhances subsequentethanol drinking patterns and exacerbates operant-mediated ethanol seeking behaviors. The motivational effects of ethanol coexist with other physiological consequences of the state of intoxication;particularly with a significant respiratory depression. Sequential exposure to the drug also sensitizesthe organism towards its disruptive effects upon respiratory neuroplasticity. In turn, the sensitizationprocess favors associative learning mechanisms that comprise the contingency existing betweenchemosensory perception of ethanol and its depressant respiratory effects. Two additional studieshave been conducted in human neonates delivered by infrequent, moderate or frequent drinkers.We employed the Neonatal Facial Coding System to evaluate facial expressions elicited by ethanolodor or a novel scent (lemon). Babies prenatally exposed to the drug exhibited significantly higherappetitive responses to ethanol odor when compared with babies delivered by infrequent drinkers. Ina second study, respiratory, cardiac and oxygen saturation parameters were assessed in babiesexposed to ethanol odor or lemon. Ethanol odor was found to significantly depress respiratory frequencies in neonates delivered by frequent drinkers. These studies demonstrate that fetal ethanolexposure recruits analogous non-associative (sensitization) and associative learning processesrelated with the establishment of ethanol preferences and with physiological disruptions of the respiratory system.237A PERSISTENT REDOX IMBALANCE UNDERLIES MALADAPTIVE BEHAVIOR INADOLESCENT OFFSPRING EXPOSED PRE- AND POST-NATALLY TO ETHANOLP. Haeger, M. Contreras, W. Plaza, S. Vargas-Roberts, E. de la Fuente-OrtegaDepartamento de Ciencias Biomedicas, Facultad de Medicina, Universidad Cat olica Del Norte, Coquimbo, 1781421, ChileEthanol intake during pregnancy may generate severe effects in the cognitive development of theoffspring. Prenatal ethanol exposure (PEE) in both human as well as animal models alters cognitivebehaviors including learning and memory, and also increases susceptibility to developing alcoholand substance use disorders. Here, we tested the hypothesis that PEE induces a long-lastingincrease in oxidative stress in the brain that can be correlated with cognitive deficits. We also hypothesized that antioxidant treatment would ameliorate PEE-induced cognitive deficits in adolescent rats.We quantified the levels of antioxidant-enzyme mRNAs in mesocorticolimbic brain regions- prefrontal cortex (PFC), ventral tegmental area (VTA) and hippocampus (Hip)- and tested the particularrole NADPH oxidase 2 (NOX2) (postsynaptic superoxide generator) on impairment of hippocampallong term plasticity (LTP) or spatial memory acquisition as well as in the increased ethanol seekingbehavior of rats developmentally-exposed to ethanol (during pregnancy and 7 days of nursing)(DEE). We observed that DEE reduced mRNA levels for antioxidant-enzymes in PFC and Hip,besides NOX2 in VTA during early adolescence (postnatal day 21). In contrast, during late adolescence (postnatal day 70), reduced NOX2 mRNA levels are observed in PFC and Hip, and of antioxidant-enzymes in VTA. Moreover, inhibition of NOX2, restored long-term potentiation in the CA1hippocampal region and rescued spatial learning deficits in DEE rats. Finally, inhibition of NOX2 intothe VTA blocked alcohol-seeking behavior. We are currently performing studies to further characterize the specific mechanisms by which NOX2 is contributing to the memory impairments and vulnerability to alcohol abuse in DEE rats. Funded by FONDECYT grant No 1140855.238THE PRELIMBIC CORTEX NEURONAL ENSEMBLES ENCODE ASSOCIATIVE MEMORIESBETWEEN ALCOHOL REWARDING EFFECTS AND CONTEXTUAL CUESF.C. Cruz, P. Palombo, P.C. Bainchi, C.R. Zaneboni, S.A. Engi, P.E. Carneiro de Oliveira,C.S. Planeta, R.M. LeaoPharmacology Department, Sao Paulo Federal University, Sao Paulo, Sao Paulo, 040023062, ~BrazilEnvironmental contexts previously associated with drug use provoke relapse to drug use in humansand reinstatement of drug seeking in animal models of drug relapse. We examined, whether contextinduced reinstatement of alcohol seeking is mediated by activation of neuronal ensembles of the prelimbic cortex. We also evaluated changes in gene expression related to alcohol seeking. To assessa causal role for the prelimbic neuronal ensembles in context-induced reinstatement of alcohol seeking, we used the Daun02 procedure to selectively inactivate these neurons. We trained c-fos-lacZtransgenic rats to self-administer alcohol in Context A and extinguished their lever-pressing in Context B. On induction day, we exposed rats to either Context A or a novel Context C for 30 min andinjected Daun02 or vehicle into prelimbic cortex 60 min later. On test day, 3 d after induction day, theability of Context A to reinstate alcohol seeking was attenuated when Daun02 was previouslyinjected after exposure to Context A (active lever presses: 16.0 4.0 Vehicle drug context vs4.0 2.0 Daun02 drug context; n = 6; p < 0.05). In addition, we assessed whether context-inducedreinstatement was associated with molecular alterations selectively induced within context-activatedFos-expressing neurons. We used fluorescence-activated cell sorting to selectively-isolate reinstatement-activated Fos-positive neurons and Fos-negative neurons in the prelimbic cortex and usedquantitative PCR to assess gene expression within these two populations of neurons. Contextinduced reinstatement was associated with increased expression of GABAa5 GABAA receptor subunit mRNA (3.04 1.09 in Fos-positive, and 1 1.15 in Fos-negative; n = 4?6; p < 0.05) and adecrease in GluA1 (0.16 0.65 and 1 0.33; respectively; n = 4?6; p < 0.05) and GluA2(0.3 1.41 and 0.99 0.89; respectively; n = 4?6; p < 0.05) AMPA receptor subunit mRNAs inonly Fos-positive neurons. Our results demonstrate an important role of the prelimbic cortex neuronal ensembles in context-induced reinstatement of alcohol seeking and that this reinstatement isassociated with unique gene alterations in Fos-expressing neurons.239EXPRESSION OF ETHANOL SENSITIVE GLYCINE RECEPTORS IN SEVERAL BRAINREGIONS IN WILD TYPE AND ALPHA1 KI MICEL.G. Aguayo1, S. Gallegos1, B. Munoz ~ 1, R. Viveros1, D.M. Lovinger2, G.E. Homanics31University of Concepcion, Concepcion, Chile, 2National Institute on Alcohol Abuse and Alcoholism,National Institutes of Health, Bethesda, MD, USA and 3University of Pittsburgh, Pittsburgh, PA15261, USASynaptic glycine receptors (GlyR) are expressed primarily in spinal cord and brain stem neurons.GlyRs are sensitive to general anesthetics, neurosteroids, Zn2+ and ethanol. Recently, GlyRs werealso found in other supratentorial regions, but their properties are largely unknown. Mesolimbicregions, such as ventral tegmental area (VTA) and nucleus accumbens (nAc), were also found toexpress GlyRs of a still unidentified molecular nature. This information is of interest because theseareas might be important for the rewarding effects of drugs of abuse. The aim of this work was toidentify the presence of GlyRs in regions of the reward system (prefrontal cortex, PFC, NAc andVTA) and to characterize electrophysiological properties and sensitivity to ethanol in WT and KI micewith ethanol insensitive alpha1 subunits. Using western blot, we detected the GlyR a1 subunit inPFC, VTA and NAc in C57BL/6J mice. These results were corroborated with immunohistochemistrystudies in coronal brain slices containing the regions of interest from adult WT (C57BL/6J). Confocalmicroscopy analysis suggests the presence of both synaptic and non-synaptic GlyRs in the threeareas. Recordings from acutely dissociated neurons showed that most neurons displayed a largecurrent (>500 pA at 1 mM of glycine). The currents had different sensitivities in the three cell typesexamined. For instance, PFC had a glycine EC50 value of 130 mM while in NAc and VTA the valueswere close to 40 mM. Interestingly in WT mice, glycine-induced current in VTA and NAc neuronswas potentiated by 50 mM ethanol whereas PFC neurons were insensitive. Glycine-induced currents in VTA and NAc neurons in alpha1 KI mice were not affected by ethanol supporting the ideathat these brain regions express a1 subunits. The results suggest that the receptor conformation andsensitivity to glycine and ethanol are different in distinct brain areas. Supported by