Effects of environmental enrichment upon ethanol-induced conditioned place preference and pre-frontal BDNF levels in adolescent and adult mice

Environmental enrichment (EE) provides a non-pharmacological tool to alter drug-induced reward, yet its effects on ethanol-induced reward remain controversial. We analyzed adolescent vs. adult (mice) differences in the influence of EE on ethanol-induced conditioned place preference (CPP). The effects of these treatments on brain-derived neurotrophic factor (BDNF) levels in the prefrontal cortex were examined in a separate group of animals. Ethanol-induced CPP was found in adults, and it was similar in EE and in animals reared under standard housing conditions (SC). Adolescents kept under EE, but not those in SC, exhibited CPP. Among SC, but not among EE, adolescents, BDNF levels were significantly lower in those treated with ethanol than in those given vehicle. These results indicate that, compared to adults, adolescent exhibited reduced sensitivity to ethanol's rewarding effects, yet the youth but not the adults exhibited sensitivity to the promoting effect of EE upon CPP by ethanol. Ethanol significantly reduced BDNF levels in adolescents reared under standard housing conditions, but not in adult mice nor in adolescents given EE housing conditions. The present results add to the plethora of adolescent-specific responses to ethanol or to environmental stimuli that may put the youth at risk for escalation of ethanol intake.Fil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Suarez, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Hoffmann, Lucas Barbosa. Universidade de Sao Paulo; BrasilFil: Rueda, André Veloso. Universidade de Sao Paulo; BrasilFil: Rae, Mariana. Universidade de Sao Paulo; BrasilFil: Marianno, Priscila. Universidade de Sao Paulo; BrasilFil: Camarini, Rosana. Universidade de Sao Paulo; Brasi

Effect of alcoholic beverages on progeny and reproduction of mice

Alcohol is the most commonly consumed substance in the world. The objective of this study was to evaluate the influence of alcoholic beverages on male reproduction and possible alterations in their offspring. The mice were divided into 4 groups: beer, wine, cachaça (a type of sugarcane rum), with ethanol concentrations of 1.9 g/kg, and control group treated with PBS. The treatment period was 35 days. The animals which received cachaça, demonstrated significant weight loss in the testes and epididymis. The alcoholic beverages promoted significant testosterone level and fertilization index diminution, and morphological alterations in the spermatozoa. The beer group presented decreased implantation sites and a high frequency of dominant lethal. The number of reabsorptions in the wine group was increased. The fermented beverages presented higher potential to induce visceral malformations, while the cachaça caused fetal skeletal malformations. The cachaça treated group presented a negative impact on semen quality and fertilization potential. The treatment with different alcoholic beverages, during spermatogenesis, demonstrated contrasting degrees of induction of toxic effects, interfering in a general aspect in male reproductive performance, fetal viability during intrauterine life, and birth defects. From the data, it is possible to infer that the distillated beverage caused more harmful effects to reproduction in this study

Environmental enrichment during pregnancy reduces ethanolinduced impairment of maternal behavior and offspring development in mice.

O consumo de álcool durante a gestação constitui um grave problema de saúde pública, uma vez que ele ultrapassa a barreira placentária e afeta o desenvolvimento embrio-fetal. Além dos efeitos diretos da exposição ao álcool no feto, o consumo durante a gestação também pode interferir no cuidado que a mãe expressa com o filhote, já que a droga parece interromper a interação entre eles, e reduzir a liberação materna de ocitocina (OT). Já o enriquecimento ambiental (EA) durante a gestação parece aumentar os comportamentos direcionados aos filhotes e também tem se mostrado capaz de modular o sistema ocitocinérgico. O objetivo do estudo foi avaliar a exposição ao EA (24h ou 3h por dia), durante a gestação, sobre os efeitos do álcool no comportamento materno, e no desenvolvimento e comportamentos da prole. Para isso, camundongos Swiss fêmeas foram divididas em quatro grupos: alojadas em gaiolapadrão e tratadas com água (CT-NE); alojadas em gaiola-padrão e tratadas com etanol (3 g/kg; EtOH-NE); alojadas em EA e tratadas com água (CT-EA); e alojadas em EA e tratadas com etanol (EtOH-EA). As fêmeas foram introduzidas no EA durante a gestação e o tratamento com etanol foi realizado por gavagem do dia de gestação (GD) 15 ao dia pós-natal (PND) 10. O comportamento materno foi avaliado no PND3 logo após o tratamento com etanol e no PND4, imediatamente antes do tratamento. A prole foi avaliada quanto ao desenvolvimento físico e reflexológico além dos seguintes comportamentos: interação social, comportamento tipo ansioso, consumo de etanol e atividade locomotora durante a adolescência; e o comportamento de agressividade na idade adulta, em machos e fêmeas. Ainda, foi avaliada a concentração plasmática de OT, o número de células imunorreativas à OT no núcleo paraventricular, e a expressão gênica da OT e seu receptor no hipotálamo. Mães do grupo EtOH-NE mostraram redução no comportamento materno, o qual foi atenuado pela exposição ao EA (grupo EtOH-EA). Foi encontrada uma redução na OT plasmática nas mães do grupo EtOH-NE, além de um maior número de células imunorreativas à OT e maior expressão gênica do peptídeo no hipotálamo das mães expostas ao EA. Em relação à prole, os descendentes do grupo EtOH-NE, tanto machos quanto fêmeas, apresentaram um atraso no desenvolvimento e menor interação social. Além disso, nos machos, foi observado um aumento da agressividade; e nos filhotes fêmeas, um aumento do consumo de etanol, menor agressividade maternal e menor atividade locomotora. Esses comportamentos não foram observados nos descendentes do grupo EtOH-EA. Assim, os resultados mostraram que a exposição ao etanol durante a gestação e lactação reduziu o comportamento materno, prejudicou o desenvolvimento da prole e induziu efeitos deletérios em comportamentos sociais, no consumo de etanol e atividade locomotora. Esses prejuízos foram atenuados quando as mães foram expostas ao EA durante a gestação.Ethanol consumption during pregnancy is a serious public health problem once it can cross the placental barrier and affect the embryo-fetal development. Besides ethanol direct effects on the fetuses, the intake along gestation and lactation may also interfere in the maternal care behavior to the offspring since ethanol appears to disrupt the dam-pups interaction, probably related to a decrease in maternal oxytocin release. Environmental enrichment (EE) housing during pregnancy may increase the maternal care behavior and modulate the oxytocinergic system. This study aimed to evaluate the effects of EE (24h or 3h/day) during pregnancy on maternal care of female Swiss mice exposed to ethanol and social behavior, ethanol consumption and development of the offspring. Females were divided into four groups: standard housing - water; standard housing - ethanol (3 g/kg); EE housing - water and EE housing - ethanol. EE housing occurred only during gestation and the dams were treated by gavage from gestational day (GD) 15 to postnatal day (PND) 10. The maternal care was evaluated in the PND3 after treatment and in PND 4, 24h after the last gavage. The physical and reflexological development, anxiety-like behavior, ethanol intake, locomotor activity, social interaction in adolescence and aggressive behavior in adulthood were evaluated in both male and female offspring. Furthermore, OT plasma concentration, number of OT-immunoreactive cells in the paraventricular nucleus (PVN), and OT gene expression in the hypothalamus were evaluated. Dams of the standard housing-ethanol group showed a variety of deficits in maternal care which was reduced by exposure to EE. A reduction in OT plasma concentration was found in mothers in the standard housing - ethanol group, in addition to an increase number of OT-immunoreactive cells in the PVN and OT gene expression of mothers exposed to EE. Regarding the offspring, the ethanol exposed puppies (standard housing - ethanol descendants) of both sexes had a delay in the physical and reflexological development and showed decreased social interaction. Females showed an increased ethanol consumption, an decreased maternal aggression and lower locomotor activity and the males exhibited an elevated aggressive behavior compared to the respective EE mice. These parameters were attenuated by the mothers exposure to EE (EE housing - ethanol descendants). Thus, the results showed that ethanol gestational disrupts maternal care, harms the development of the offspring and induces deleterious effects in social parameters, ethanol consumption and locomotor activity during their adolescence/adulthood. These harmful effects were attenuated when dams were exposed to EE during pregnancy

C57BL/6 mice housed in enriched environment present lower ethanol consumption after stress.

A retomada do consumo de etanol após abstinência é uma característica da dependência. O enriquecimento ambiental (EA) parece minimizar os efeitos de drogas de abuso, assim como a naltrexona (NTX). O estudo avaliou se EA, durante abstinência e associado ou não à NTX, alterou o consumo de etanol. Camundongos C57BL/6 foram expostos ao etanol 2h/dia. Após fase de aquisição, os animais foram separados em grupos. Os animais foram alojados em condições padrões e o outro em EA, 24h/dia ou 3h/dia. Após privação, os animais voltaram a ter acesso ao etanol semanalmente. Na última semana, tiveram acesso ao etanol por 24h e antes da reexposição foram submetidos ao estresse de contenção por 1h. Só neste caso, os grupos EA apresentaram uma redução no consumo de 24h. Ainda, outro experimento foi realizado associando o EA a baixas doses de NTX, mas não foram observadas alterações. Os resultados sugerem que o EA pode ajudar o animal a lidar melhor com o estresse, o que o protegeria de um comportamento de maior consumo de etanol.The excessive ethanol consumption after abstinence is a feature of addiction. Environmental enrichment (EE) appears to minimize drug cravings, as well as naltrexone (NTX). The study evaluated whether EE during abstinence and with or without NTX, altered ethanol consumption. C57BL/6 mice were exposed to ethanol 2h/day. After an acquisition phase, mice were distributed into groups. The animals were housed in standard condition and the other in EE, 24h/day or 3h/day. After withdrawal, the animals returned to ethanol access weekly. On the last week, mice had access to ethanol for 24h and before re-exposure were subjected to restraint stress for 1h. EE groups decreased the ethanol consumption when mice had 24h free access to ethanol. Another experiment was performed with EE in association to low doses of NTX, but no differences in consumption were observed. The results suggests that EE may help the animal to cope better with stressful situations, resulting in blunted ethanol drinking

Environmental Enrichment Blunts Ethanol Consumption after Restraint Stress in C57BL/6 Mice

<div><p>Elevated alcohol intake after abstinence is a key feature of the addiction process. Some studies have shown that environmental enrichment (EE) affects ethanol intake and other reinforcing effects. However, different EE protocols may vary in their ability to influence alcohol consumption and stress-induced intake. The present study evaluated whether short (3 h) or continuous (24 h) EE protocols affect ethanol consumption after periods of withdrawal. Mice were challenged with stressful stimuli (24 h isolation and restraint stress) to evaluate the effects of stress on drinking. Male C57BL/6 mice were subjected to a two-bottle choice drinking-in-the-dark paradigm for 15 days (20% ethanol and water, 2 h/day, acquisition phase). Control mice were housed under standard conditions (SC). In the first experiment, one group of mice was housed under EE conditions 24 h/day (EE24h). In the second experiment, the exposure to EE was reduced to 3 h/day (EE3h). After the acquisition phase, the animals were deprived of ethanol for 6 days, followed by 2 h ethanol access once a week. Animals were tested in the elevated plus maze (EPM) during ethanol withdrawal. During the last 2 weeks, the mice were exposed to 24 h ethanol access. A 1-h restraint stress test was performed immediately before the last ethanol exposure. EE24h but not EE3h increased anxiety-like behavior during withdrawal compared to controls. Neither EE24h nor EE3h affected ethanol consumption during the 2 h weekly exposure periods. However, EE24h and EE3h mice that were exposed to acute restraint stress consumed less ethanol than controls during a 24 h ethanol access. These results showed that EE reduces alcohol intake after an acute restraint stress.</p></div

Experiment 2.

<p>(A) Ethanol consumption for 2 h/day during 15 days of acquisition phase. (B-D) Elevated plus maze test: (B) percent time on open arms, (C) number of open arm entries, and (D) total number of arm entries. (E) Ethanol intake during 2 h access to two-bottle choice once per week. Ethanol intake calculations followed the same criteria as described for the first experiment. (F) Ethanol intake (g/kg) during 24 h of access to two-bottle choice on weeks 3 and 4. (G) Water intake during 2 h access to two-bottle choice. Water intake calculations followed the same criteria as described for the first experiment. (H) Water intake (ml) during 24h. Gray bars represent the measures of intake after exposure to the restraint stress procedure. The data are expressed as mean ± SEM. *<i>p</i> < 0.05, compared with day 3 in A, compared with the other re-exposure weeks in E, and compared with the EE group on the previous week without stress in F; ⁺<i>p</i> < 0.05, compared with SC group; ^#<i>p</i> < 0.05, compared with weeks 2 and 3.</p

Experiment 1.

<p>(A) Ethanol consumption for 2 h/day during 15 days of acquisition phase. (B) Blood ethanol concentration (mg/ml) plotted against ethanol consumed (g/kg) during 2 h of ethanol access. Positive correlation was found between the amount of ethanol consumed and BECs (<i>r</i>^<i>2</i> = 0.41, <i>p</i> < 0.05). (C-E) Elevated plus maze test: (C) percent time on open arms, (D) number of open arm entries, and (E) total number of arm entries. (F) Ethanol intake during 2 h access to two-bottle choice once a week. Ethanol intake was converted to percent of basal ethanol consumption. Basal ethanol consumption was calculated by averaging the absolute consumption of the last 5 days of acquisition phase, and converted as 100% (week 0). (G) Ethanol intake (g/kg) during 24 h of access to two-bottle choice on weeks 5 and 6. (H) Water intake (ml) during 2 h access to two-bottle choice. Water intake was converted to percent of basal water consumption. Basal water consumption was calculated by averaging the absolute consumption of the last 5 days of acquisition phase, and converted as 100% (week 0). (I) Water intake (ml) during 24 h. Gray bars represent the measures of intake after exposure to the restraint stress procedure. The data are expressed as mean ± SEM, except in B. *<i>p</i> < 0.05, compared with days 1, 2, and 3 in A, compared with prior re-exposure weeks in F, H, and I, and compared with the EE group on the previous week without stress in G; ⁺<i>p</i> < 0.05, compared with SC group.</p

Carbetocin Inhibits Behavioral Sensitization to Ethanol in Male and Female Mice, Independent of Corticosterone Levels

Oxytocin (OXT), a pro-social peptide, is increasingly recognized as a potential protective substance against drug addiction. In the context of ethanol, previous research has shown OXT’s properties in reducing self-administration, alleviating motor impairment in rodents, and reducing craving in humans. However, its role in behavioral sensitization, a neuroadaptive response resulting from repeated drug exposure linked to an increased drug incentive, remains unexplored. OXT is recognized for its role in regulating the hypothalamic–pituitary–adrenal (HPA) axis, in which corticosterone is acknowledged as a significant factor in the development of behavioral sensitization. This study aimed to investigate the effects of carbetocin (CBT), an analogue of OXT, on the expression of behavioral sensitization to ethanol and the concurrent alterations in plasma corticosterone levels in male and female Swiss mice. We also aimed to confirm previous studies on OXT’s impact on ethanol consumption in male mice, but with a focus on CBT, using the two-bottle choice model and the drinking in the dark (DID) methodology. For the sensitization study, the mice received either ethanol (1.8 g/kg, i.p.) or saline treatments daily for 15 consecutive days, followed by treatment with carbetocin (0.64 mg/kg, i.p.) or a vehicle for 6 days. Subsequently, on day 22, all the animals underwent an ethanol challenge to assess the expression of behavioral sensitization. The plasma corticosterone levels were measured on days 21 and 22. The CBT effectively prevented the expression of ethanol-induced behavioral sensitization in both male and female subjects, with no alterations having been detected in their corticosterone levels. In the ethanol consumption study, following an initial phase of ethanol acquisition, the male mice underwent a 6-day treatment with CBT i.p. or saline before being re-exposed to ethanol. We also found a reduction in their ethanol consumption due to the CBT treatment. In conclusion, carbetocin emerges as a promising and effective intervention for mitigating ethanol-induced behavioral sensitization and reducing ethanol intake, highlighting its potential significance in alcohol addiction treatment

Effect of alcoholic beverages on progeny and reproduction of mice

ABSTRACT Alcohol is the most commonly consumed substance in the world. The objective of this study was to evaluate the influence of alcoholic beverages on male reproduction and possible alterations in their offspring. The mice were divided into 4 groups: beer, wine, cachaça (a type of sugarcane rum), with ethanol concentrations of 1.9 g/kg, and control group treated with PBS. The treatment period was 35 days. The animals which received cachaça, demonstrated significant weight loss in the testes and epididymis. The alcoholic beverages promoted significant testosterone level and fertilization index diminution, and morphological alterations in the spermatozoa. The beer group presented decreased implantation sites and a high frequency of dominant lethal. The number of reabsorptions in the wine group was increased. The fermented beverages presented higher potential to induce visceral malformations, while the cachaça caused fetal skeletal malformations. The cachaça treated group presented a negative impact on semen quality and fertilization potential. The treatment with different alcoholic beverages, during spermatogenesis, demonstrated contrasting degrees of induction of toxic effects, interfering in a general aspect in male reproductive performance, fetal viability during intrauterine life, and birth defects. From the data, it is possible to infer that the distillated beverage caused more harmful effects to reproduction in this study