Search bioRxiv⌕ Search

Biology subjects

De Vries, T. J.

Publications and source records attributed to De Vries, T. J..

3 recordsLinked to original sources

Lateral hypothalamic GABAergic neurons encode alcohol memories.

In alcohol use disorder the alcohol memories persist during abstinence, and exposure to stimuli associated with alcohol use can lead to relapse. This highlights the importance of investigating the neural substrates underlying not only relapse, but also encoding and expression of alcohol memories. GABAergic neurons in the Lateral Hypothalamus (LH- GABA) have been shown to be critical for food-cue memories and motivation, however the extent to which this role extends to alcohol-cue memories and motivations remains unexplored. In this study, we aimed to describe how alcohol related memories are encoded and expressed in LH GABAergic neurons. Our first step was to monitor LH-GABA calcium transients during acquisition, extinction, and reinstatement of an alcohol-cue memory using fiber photometry. We trained the rats on a Pavlovian conditioning task where one conditioned stimulus (CS+) predicted alcohol (20% EtOH) and another conditioned stimulus (CS-) had no outcome. We then extinguished this association through non-reinforced presentations of the CS+ and CS-, finally in two different groups we measured relapse under non-primed and alcohol primed induced reinstatement. Our results show that initially both cues caused increased LH-GABA activity, and after learning only the alcohol-cue increased LH-GABA activity. After extinction this activity decreases, and we found no differences in LH- GABA activity during reinstatement in either group. Next, inhibited LH-GABA neurons with optogenetics to show that activity of these neurons is necessary for the formation of an alcohol-cue associations. These findings suggest that LH-GABA might be involved in attentional processes modulated by learning.

neuroscience↗

Role of anterior insula cortex in context-induced relapse of nicotine-seeking

Tobacco use is the leading cause of preventable death worldwide, and relapse during abstinence remains the key barrier to successful treatment of tobacco addiction. During abstinence, environmental contexts associated with nicotine use can induce craving and contribute to relapse. The insular cortex (IC) is thought to be a critical substrate of nicotine addiction and relapse. However, its specific role in context-induced relapse of nicotine-seeking is not fully known. In this study, we report a novel rodent model of context-induced relapse to nicotine-seeking after punishment-imposed abstinence, which models self-imposed abstinence through increasing negative consequences of excessive drug use. Using the neuronal activity marker Fos we find that the anterior (aIC), but not the middle or posterior IC, shows increased activity during context-induced relapse. Combining Fos with retrograde labelling of aIC inputs, we show projections to aIC from contralateral aIC and basolateral amygdala exhibit increased activity during context-induced relapse. Next, we used fiber photometry in aIC and observed phasic increases in aIC activity around nicotine-seeking responses during self-administration, punishment, and the context-induced relapse tests. Next, we used chemogenetic inhibition in both male and female rats to determine whether activity in aIC is necessary for context-induced relapse. We found that chemogenetic inhibition of aIC decreased context-induced nicotine-seeking after either punishment- or extinction-imposed abstinence. These findings highlight the critical role nicotine-associated contexts play in promoting relapse, and they show that aIC activity is critical for this context-induced relapse following both punishment and extinction imposed abstinence.

neuroscience↗

Stress vulnerability promotes an alcohol prone phenotype in a preclinical model of sustained depression

Major depression and alcohol-related disorders frequently co-occur. Depression severity weighs on the magnitude and persistence of comorbid alcohol use disorder (AUD), with severe implications for disease prognosis. Here, we investigated whether depression vulnerability drives propensity to AUD at the preclinical level. We used the social defeat-induced persistent stress (SDPS) model of chronic depression in combination with operant alcohol self-administration (SA). Male Wistar rats were subjected to social defeat (5 episodes) and prolonged social isolation (~12 weeks) and subsequently classified as SDPS-prone or SDPS-resilient based on their affective and cognitive performance. Using an operant alcohol SA paradigm, acquisition, motivation, extinction and cue-induced reinstatement of alcohol-seeking were examined in the two subpopulations. SDPS-prone animals showed increased alcohol SA, excessive motivation to acquire alcohol, persistent alcohol-seeking despite alcohol unavailability, extinction resistance and increased cue-induced relapse; the latter could be blocked by the 2 adrenoreceptor agonist guanfacine. In SDPS-resilient rats, prior exposure to social defeat increased alcohol SA without affecting any other measures of alcohol-seeking and -taking. Our data revealed that depression proneness confers vulnerability to alcohol, emulating patterns of alcohol dependence seen in human addicts, and that depression resilience to a large extent protects from the development of AUD-like phenotypes. Furthermore, our data suggest that stress exposure alone, independently of depressive symptoms, alters alcohol intake in the long-term.

animal behavior and cognition↗