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Altered dopamine (DA) transporter densities have been implicated in mechanisms of vulnerability and relapse in human alcoholics. The regional distribution and density of the DA transporter was studied in alcohol-preferring vervet monkeys to investigate baseline status and regulation of the DA transporter at different stages of chronic alcohol drinking. Combined ligand binding and in vitro autoradiography of the cocaine congener [125I]RTI-55 (beta-CIT) demonstrated a significant increase in DA transporter densities in abstinent alcohol-preferring monkeys over those in alcohol-avoiding monkeys. Chronic alcohol consumption down-regulated DA transporter densities, and this effect was reversed by acute withdrawal. These results demonstrate that the DA transporter is regulated by alcohol exposure and suggest that increased DA transporter densities may be a phenotypic marker of alcohol preference in vulnerable monkeys.

AbstractObjective: The marked increase in the prevalence of obesity in the United States has recently been attributed to the increased fructose consumption. To determine if and how fructose might promote obesity in an animal model, we measured body composition, energy intake, energy expenditure, substrate oxidation, and several endocrine parameters related to energy homeostasis in mice consuming fructose.Research Methods and Procedures: We compared the effects of ad libitum access to fructose (15% solution in water), sucrose (10%, popular soft drink), and artificial sweetener (0% calories, popular diet soft drink) on adipogenesis and energy metabolism in mice.Results: Exposure to fructose water increased adiposity, whereas increased fat mass after consumption of soft drinks or diet soft drinks did not reach statistical significance (n = 9 each group). Total intake of energy was unaltered, because mice proportionally reduced their caloric intake from chow. There was a trend toward reduced energy expenditure and increased respiratory quotient, albeit not significant, in the fructose group. Furthermore, fructose produced a hepatic lipid accumulation with a characteristic pericentral pattern.Discussion: These data are compatible with the conclusion that a high intake of fructose selectively enhances adipogenesis, possibly through a shift of substrate use to lipogenesis.

Neuroimaging studies have demonstrated gray matter (GM) volume abnormalities in substance users. While the majority of substance users are polysubstance users, very little is known about the relation between GM volume abnormalities and polysubstance use.In this study we assessed the relation between GM volume, and the use of alcohol, tobacco, cocaine and cannabis as well as the total number of substances used, in a sample of 169 males: 15 non-substance users, 89 moderate drinkers, 27 moderate drinkers who also smoke tobacco, 13 moderate drinkers who also smoke tobacco and use cocaine, 10 heavy drinkers who smoke tobacco and use cocaine and 15 heavy drinkers who smoke tobacco, cannabis and use cocaine.Regression analyses showed that there was a negative relation between the number of substances used and volume of the dorsal medial prefrontal cortex (mPFC) and the ventral mPFC. Without controlling for the use of other substances, the volume of the dorsal mPFC was negatively associated with the use of alcohol, tobacco, and cocaine. After controlling for the use of other substances, a negative relation was found between tobacco and cocaine and volume of the thalami and ventrolateral PFC, respectively.These findings indicate that mPFC alterations may not be substance-specific, but rather related to the number of substances used, whereas, thalamic and ventrolateral PFC pathology is specifically associated with tobacco and cocaine use, respectively. These findings are important, as the differential alterations in GM volume may underlie different cognitive deficits associated with substance use disorders.

Abstract Aims Alcohol use alters the reward signaling processes contributing to the development of addiction. We studied the effects of alcohol use disorder (AUD) on brain regions and blood of deceased women and men to examine sex-dependent differences in epigenetic changes associated with AUD. We investigated the effects of alcohol use on the gene promoter methylation of GABBR1 coding for GABAB receptor subunit 1 in blood and brain. Methods We chose six brain regions associated with addiction and the reward pathway (nucleus arcuatus, nucleus accumbens, the mamillary bodies, amygdala, hippocampus and anterior temporal cortex) and performed epigenetic profiling of the proximal promoter of the GABBR1 gene of post-mortem brain and blood samples of 17 individuals with AUD pathology (4 female, 13 male) and 31 healthy controls (10 female, 21 male). Results Our results show sex-specific effects of AUD on GABBR1 promoter methylation. Especially, CpG −4 showed significant tissue-independent changes and significantly decreased methylation levels for the AUD group in the amygdala and the mammillary bodies of men. We saw prominent and consistent change in CpG-4 across all investigated tissues. For women, no significant loci were observed. Conclusion We found sex-dependent differences in GABBR1 promoter methylation in relation to AUD. CpG-4 hypomethylation in male individuals with AUD is consistent for most brain regions. Blood shows similar results without reaching significance, potentially serving as a peripheral marker for addiction-associated neuronal adaptations. Further research is needed to discover more contributing factors in the pathological alterations of alcohol addiction to offer sex-specific biomarkers and treatment.

It has been estimated that more than 80% of alcoholics are also nicotine dependent and that, vice versa, the rate of alcoholism is substantially increased by a factor of 4-10 in the nicotine-dependent population. However, the cause for this very high degree of comorbidity is still largely unknown. At the molecular and cellular level, both drugs have very different mechanisms of action. Nicotine specifically activates ligand-gated ion channels in the brain, which are normally gated by acetylcholine, while alcohol interacts with various neurotransmitter receptors. Despite this diversity, both drugs seem to engage the endogenous opioid system as a modulator of some of its pharmacological effect. An acute exposure to nicotine or alcohol leads to a release of opioid peptides in specific brain regions, thus resulting in an activation of their corresponding receptors. If the brain is exposed repeatedly or chronically to these drugs, adaptive changes in the level and expression of opioid peptides and receptors occur. These adaptive changes are thought to contribute to the homeostatic or allostatic adaptations of the brain, which have been associated with drug dependence. This review summarizes pharmacological and genetic studies in animal models and in humans that have addressed the role of specific opioid peptides and receptors in various stages of the addiction process.

We present a protocol for the biosensor Cell-Fit-HD4D. It enables long-term monitoring and correlation of single-cell fate with subcellular-deposited energy of ionizing radiation. Cell fate tracking using widefield time-lapse microscopy is uncoupled in time from confocal ion track imaging. Registration of both image acquisition steps allows precise ion track assignment to cells and correlation with cellular readouts. For complete details on the use and execution of this protocol, please refer to Niklas et al. (2022).

AbstractActivation of potassium (K+) currents plays a critical role in the control of programmed cell death. Because pituitary adenylate cyclase‐activating polypeptide (PACAP) has been shown to inhibit the apoptotic cascade in the cerebellar cortex during development, we have investigated the effect of PACAP on K+ currents in cultured cerebellar granule cells using the patch‐clamp technique in the whole‐cell configuration. Two types of outward K+ currents, a transient K+ current (IA) and a delayed rectifier K+ current (IK) were characterized using two different voltage protocols and specific inhibitors of K+ channels. Application of PACAP induced a reversible reduction of the IK amplitude, but did not affect IA, while the PACAP‐related peptide vasoactive intestinal polypeptide had no effect on either types of K+ currents. Repeated applications of PACAP induced gradual attenuation of the electrophysiological response. In the presence of guanosine 5′‐[γthio]triphosphate (GTPγS), PACAP provoked a marked and irreversible IK depression, whereas cell dialysis with guanosine 5′‐[βthio]diphosphate GDPβS totally abolished the effect of PACAP. Pre‐treatment of the cells with pertussis toxin did not modify the effect of PACAP on IK. In contrast, cholera toxin suppressed the PACAP‐induced inhibition of IK. Exposure of granule cells to dibutyryl cyclic adenosine monophosphate (dbcAMP) mimicked the inhibitory effect of PACAP on IK. Addition of the specific protein kinase A inhibitor H89 in the patch pipette solution prevented the reduction of IK induced by both PACAP and dbcAMP. PACAP provoked a sustained increase of the resting membrane potential in cerebellar granule cells cultured either in high or low KCl‐containing medium, and this long‐term depolarizing effect of PACAP was mimicked by the IK specific blocker tetraethylammonium chloride (TEA). In addition, pre‐incubation of granule cells with TEA suppressed the effect of PACAP on resting membrane potential. TEA mimicked the neuroprotective effect of PACAP against ethanol‐induced apoptotic cell death, and the increase of caspase‐3 activity observed after exposure of granule cells to ethanol was also significantly inhibited by TEA. Taken together, the present results demonstrate that, in rat cerebellar granule cells, PACAP reduces the delayed outward rectifier K+ current by activating a type 1 PACAP (PAC1) receptor coupled to the adenylyl cyclase/protein kinase A pathway through a cholera toxin‐sensitive Gs protein. Our data also show that PACAP and TEA induce long‐term depolarization of the resting membrane potential, promote cell survival and inhibit caspase‐3 activity, suggesting that PACAP‐evoked inhibition of IK contributes to the anti‐apoptotic effect of the peptide on cerebellar granule cells.

Alcoholism and alcohol abuse represent a significant medical and societal problem, and have been thoroughly investigated in humans as well as using animal models. A less well understood aspect of alcohol related disorders is the possible effect of this drug on offspring whose parents were exposed prior to conception. The zebrafish has been successfully employed in alcohol research, however, the effect of exposing the parents to alcohol before fertilization of the eggs on offspring has not been demonstrated in this species. In this proof of concept study, we attempt to address this hiatus. We exposed both adult male and female zebrafish to 0.0% (control) or 0.5% (vol/vol) alcohol chronically for 7 days, subsequently bred the fish within their respective treatment group, collected the fertilized eggs, allowed them to develop, and tested the behavior of free-swimming offspring at their age of 7-9 days post-fertilization. We conducted the analysis in two genetically distinct quasi-inbred strains of zebrafish, AB and TL. Although gross morphology and general activity of the fish appeared unaffected, we found significant behavioral alterations in offspring of alcohol exposed parents compared to offspring of control parents in both strains. These alterations included robustly increased duration and reduced frequency of immobility, increased turn angle, and increased intra-individual variance of turn angle in offspring of alcohol exposed parents in both strains. The mechanisms underlying these behavioral effects or whether the effects are due to exposure of the father, the mother, or both to alcohol are unknown. Nevertheless, our results now set the stage for future studies with zebrafish that will address these questions.