Investigating the role of cognitive bias in individual susceptibility to transition from controlled use to uncontrolled alcohol abuse in rats

Agata Cieslik-Starkiewicz

Affective Cognitive Neuroscience Laboratory,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Alcohol Use Disorder (AUD) is a prevalent mental disorder characterized by progressive escalation of alcohol intake and repeated cycles of remission and relapse. In recent years, growing attention has been paid to cognitive biases as potential factors contributing to the development of AUD. However, establishing a causal relationship between cognitive biases and AUD remains a challenge.

The study aimed to determine the role of biased cognition in individual susceptibility to transitioning from controlled alcohol use to compulsive abuse. I examined whether sensitivity to positive and negative feedback influences the acquisition and maintenance of alcohol-seeking behaviors in rats. Feedback sensitivity was assessed using probabilistic reversal learning tests. After inducing alcohol consumption through intermittent free access, I evaluated how sensitivity to feedback affects compulsive seeking under punishment, motivation, extinction of alcohol-seeking responses, and reinstatement after abstinence. Rats with lower sensitivity to positive feedback showed greater motivation to seek alcohol after experiencing negative consequences and were more likely to reinstate instrumental responses after abstinence. In contrast, high sensitivity to negative feedback reduced susceptibility to compulsive alcohol-seeking and accelerated the extinction of alcohol-seeking behaviors. I also examined how optimism and pessimism interact with alcohol-related behaviors in rats. Animals were subjected to ambiguous-cue interpretation tests to assess judgment bias, then tested under free-access and instrumental paradigms. I found that under free access conditions, "pessimistic" rats consumed more alcohol than "optimistic" rats

These findings suggest that different aspects of biased cognition such as sensitivity to feedback and judgment bias, influence vulnerability to the shift from controlled to compulsive alcohol use. This may deepen our understanding of AUD mechanisms and support the development of targeted therapeutic strategies.

Investigating the role of cognitive bias in individual susceptibility to transition from controlled use to uncontrolled alcohol abuse in rats

Michal Piksa

Affective Cognitive Neuroscience Laboratory,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

In an era marked by the rapid spread of online misinformation, cognitive biases such as confirmation bias play a critical role in shaping public beliefs, especially around polarizing topics like vaccination. Understanding and addressing these biases is essential for countering false narratives. 

My goal was to test whether making people more aware of confirmation bias could help them better distinguish between true and false information, regardless of topic. I conducted an online study with 1,479 participants with varying attitudes toward vaccination. Half received an intervention designed to raise awareness about confirmation bias; the other half did not. Afterwards, all participants evaluated the truthfulness of a series of general (non-vaccine-related) factual and false claims.

I found that the intervention significantly improved participants' ability to identify misinformation, but only among those who initially held the most negative views about COVID-19 vaccines.
These findings suggest that increasing awareness of confirmation bias can be an effective strategy to counter misinformation, particularly for individuals most vulnerable to it. I believe this approach holds promise for future public health interventions.

When the whole is greater than the sum of its parts: the role of simultaneous modulation of histamine H3 and sigma-1 receptors in the treatment of neuropathic pain

Katarzyna Szczepańska, Tadeusz Karcz, Maria Dichiara, M. Carmen Ruiz-Cantero, Szczepan  Mogilski, Enrique J. Cobos, Holger Stark, Steffen Pockes, Ilona Obara, Emanuele Amata, Katarzyna Kieć-Kononowicz, Andrzej J. Bojarski

Department of Medicinal Chemistry,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Neuropathic pain affects between 1.3% and 17.9% of the global population. It can result from a variety of pathological conditions, including metabolic diseases, infections, stroke, or cancer. Despite progress in understanding the mechanisms underlying neuropathic pain, only about 33% of patients achieve effective pain control using currently available medications. To date, no therapy has demonstrated long-term efficacy and good tolerability in treating this condition.

A promising approach in pharmacotherapy is the use of pharmacodynamic synergism, in which simultaneous action on different biological targets leads to a therapeutic effect greater than the sum of individual drug actions. In this context, multi-target directed ligands (MTDLs) – compounds designed to modulate the activity of more than one receptor or signaling pathway – are gaining increasing attention. Unlike traditional single-target drugs, MTDLs may enhance treatment efficacy, reduce the risk of side effects, and limit the development of drug tolerance.

Importantly, recent studies have shown that some histamine H3 receptor (H3R) antagonists under clinical investigation also display affinity for sigma-1 receptors (σ1R), which may play a crucial role in their pharmacological profile.¹ Moreover, both H3R and σ1R are involved in the pathophysiological mechanisms of nociceptive and neuropathic pain, and their antagonists may represent promising candidates for the development of innovative analgesics.

Interestingly, in our studies, we demonstrated that co-administration of a highly selective H3R antagonist (JNJ 5207852) and a selective σ1R antagonist (S1RA) resulted in a stronger analgesic effect than when the compounds were administered individually (an ineffective dose of S1RA significantly enhanced the effect of an effective dose of JNJ 5207852).² This type of synergistic interaction between two distinct mechanisms may be highly beneficial for the development of effective pain treatments. Furthermore, we have developed a series of dual H3R/σ1R antagonists,³ among which the most active compound, KSK107, demonstrated exceptionally high analgesic efficacy in both nociceptive and neuropathic pain models, surpassing that of selective ligands (JNJ 5207852, S1RA) and opioids. These findings confirm the strong therapeutic potential of KSK107 and support the concept of multi-target modulation of H3R and σ1R as a novel strategy in pain treatment. Further research on this compound may contribute to the development of more effective and safer analgesic therapies.

The research was supported by the National Science Centre, Poland, under grant Opus 23 (2022/45/B/NZ7/03101).

[1] Riddy DM, et al. Neuropharmacology. 2019 Jan;144:244-255.

[2] Mogilski S, et al. Pharmaceuticals (Basel). 2023 Oct 17;16(10):1481.

[3] Szczepańska K, et al. J Med Chem. 2023 Jul 27;66(14):9658-9683.

Judgement Bias Tests and Sentience

Elizabeth S. Paul

Bristol Veterinary School, University of Bristol,

Bristol, UK

It is not known which living organisms, aside from humans, have the capacity to have conscious experiences, and in particular, the capacity to feel pleasures and pains. But this is an ethically important problem - central both to our understanding of suffering in non-human animals, and to our understanding of the evolution of affective states/disorders in humans.

Here, I consider the question of whether judgement bias tests may be able to demonstrate the presence of conscious affective states in animals. Such tests come in a number of forms (e.g. Go/No-go; Go/Go; Pavlovian; Instrumental) and are used in both humans and animals to assess affective states/traits. Among animals, such tests have mostly been used with mammals. But these tests have also been successfully used to assay positive and negative states in non-mammalian species, including fish, ants and bees, by employing discrimination-learning tasks to demonstrate ‘optimistic-like’ and ‘pessimistic-like’ responses to affectively ambiguous stimuli.

The processes involved in determining the outcomes of judgement bias tests can be interrogated in a number of ways. For example, it is possible to describe different test outcomes at an algorithmic-level, a psychological-level, and at a neuronal/neuropharmacological-level. While all of these are valid approaches, it is important to see that they are also have very different contributions to make to our understanding of the actual felt experiences of individual animals showing judgement biases.

I suggest that, while optimistic and pessimistic-like biases in decision making are likely to have adaptive functions for many animals, these are likely to be effected either consciously or non-consciously, depending on the species involved. I propose that by finding markers for decisions that do and do not make use of conscious affect in humans, it may be possible to use judgement bias tests as indicators of sentience in a variety of animal species.

Unique strain-specific characteristics of Wistar Kyoto rats are reflected at both behavioral and biochemical levels

Kolasa Magdalena, Solich Joanna, Hajto Jacek, Borczyk Małgorzata, Korostyński Michał, Roman Adam, Mielczarek Przemysław, Pabian Paulina, Faron-Górecka Agata

 Department of Pharmacology,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Wistar Kyoto (WKY) rats are a valuable preclinical model of treatment-resistant depression (TRD), as they show several features similar to human major depressive disorder—such as increased stress sensitivity and anxiety-like behavior—and they do not respond to standard antidepressant treatments.

Strain-specific behavioral differences (WKY vs. Wistar rats) were observed in classical tests, including the novel object recognition (NOR) test, social interaction (SI) test, and forced swim test (FST), following a single dose of psilocybin (0.3 mg/kg) (Kolasa et al., 2024).

Additionally, we also performed biochemical analyses of the prefrontal cortex, examining miRNA expression (4 hours after treatment) and proteomic changes (7 days after treatment). Several miRNAs, including miR-212-3p and miR-34a-5p, differed between the strains and may play a role in antidepressant response. Proteomic analysis showed significant differences between WKY and WIS rats, especially in metabolic pathways. Psilocybin altered the expression of proteins involved in RNA metabolism and mRNA processing.

In summary, these findings highlight significant behavioral and molecular differences between WKY and WIS rats, evident both at baseline and following psilocybin treatment.

Acknowledgements

The study was funded by Intramural grant “Exploring molecular correlates of psilocybin action in the animal model of treatment-resistant depression” and Statutory Activity of the Laboratory of Biochemical Pharmacology Maj Institute of Pharmacology PAS.

Sex-specific effects of Enrichment and Prediction Error on Rat Affect

Nick Cherbanich, Vikki Neville, Liz Paul, Mike Mendl

Bristol Veterinary School, University of Bristol,

Bristol, UK

TBA

        
TBA

Magdalena Bialon

TBA

Stress-Induced Alterations in Immune Checkpoint Signaling: Insights from Experimental Depression

Katarzyna Curzytek, Stanisław Malicki, Kinga Kamińska, Anna Gąsiorek, Marta Kubera

Department of Experimental Neuroendocrinology,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Introduction:

Emerging research underscores the complex role of immune mechanisms in the pathogenesis of depressive disorders. Accumulating evidence from neurobiological and immunological studies suggests that both psychological and physical stressors can heighten vulnerability to psychiatric illnesses, particularly major depressive disorder. Stress and depression share overlapping biological pathways, especially in the context of inflammation, metabolic disturbances, and coagulation processes. These shared features emphasize the importance of neuroimmune interactions, where dysregulated immune-to-brain signaling may compromise central nervous system function and contribute to mood-related disturbances.

Methods:

This study explored the potential involvement of immune checkpoint molecules—specifically PD-1 and its ligand PD-L1—in the molecular mechanisms associated with depression. Experimental analyses were performed using two animal models: Wistar Kyoto rats, which exhibit traits of treatment-resistant depression, and Wistar rats exposed to a chronic restraint stress paradigm. Behavioral assessments were conducted using standard tests for cognitive and affective symptoms, and gene expression analyses of PD-1 and PD-L1 were carried out in both central (hippocampus, frontal cortex) and peripheral tissues (spleen, blood-derived immune cells).

Results:

Findings revealed a differential, tissue-specific modulation of PD-1/PD-L1 expression across models. PD-L1 was notably downregulated in the hippocampus in both models, suggesting a link to stress-related neural vulnerability. Meanwhile, peripheral expression of these molecules also varied, with consistent upregulation of PD-1 in circulating immune cells, indicating systemic immune activation. Distinct expression patterns in genetically predisposed versus stress-induced models of depression suggest differing underlying immune regulatory processes. Furthermore, reduced PD-L1 expression in the hippocampus was associated with impairments in recognition memory, highlighting potential functional consequences of altered immune signaling in the brain.

Conclusions:

These findings suggest that immune checkpoint pathways are differentially regulated in models of depression driven by genetic and environmental factors. The observed central and peripheral alterations in PD-1/PD-L1 signaling may reflect complex neuroimmune dynamics contributing to depressive symptomatology. Understanding these pathways could provide insights into novel immunomodulatory strategies for mood disorders.

The effect of FPR2 agonists on the immune profile of microglia obtained from  9-months old WT and APPNLF/NLF mice: study in the prodromal period of Alzheimer's disease

Łukowicz K., Grygier B. , Frydrych J.,  Trojan E., Lacivita E2. Basta-Kaim A.

 Department of Experimental Neuroendocrinology,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Neuroinflammation is recognized as a key contributor to the progression of Alzheimer’s diseas (AD)e , driven in part by the chronic activation of immunocompetent cells within the central nervous system, Microglial polarization toward pro- or anti-inflammatory phenotypes plays a critical role in modulating disease outcomes. One of the key regulators of this process is the formyl peptide receptor 2 (FPR2), a G protein-coupled receptor whose functional response is highly dependent on ligand specificity, allowing it to mediate microglia immune response  [1]

The present study investigating the profile of microglia activation under basal condition and following stimulation with lipopolysaccharide (LPS). Moreover, the effects of agonists of the FPR2 receptor was evaluated. The primary microglial cells obtained from the knock-in murine model of late-onset Alzheimer's disease (APPNLF/NLF), and wild-type mice (WT) isolated from from 9-month mice were used in experiments. Subsequently, total mRNA was isolated and reverse-transcribed into cDNA, followed by RT-PCR analysis to quantify the expression levels of genes associated with pro- and anti-inflammatory microglial polarization.

A significant upregulation of IL-6, IL-18, IL-33 and p16 was observed in basal condition in microglia in APPNLF/NLF mice compared to WT (controls). This pro-inflammatory status was also observed in cultures after immune stimulation with LPS. Among the tested FPR2 agonists, compound Fz6 was the most potent and able to lowering elevated expression of p16 and IL33 in adult APPNLF/NLF mice.

The obtained results indicate proinflammatory phenotype of microglial cells in the prodromal phase of AD compared to WT control animals. Moreover, we found that  some of the FPR2 agonists are capable of modulating microglial activity in the pro-resolving direction.

The impact of tryptamide on the activity of primary microglial cultures

Grygier B., Leśkiewicz M., Regulska M., Trojan E., Kaminska K, Basta-Kaim A.

 Department of Experimental Neuroendocrinology,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

INTRODUCTION: Tryptamide (TRP) is a pharmacologically active compound with well-documented anti-inflammatory and analgesic effects, primarily studied in the context of peripheral organ systems. Existing data demonstrate TRP’s efficacy in both immunologically specific and non-specific models of experimentally induced inflammation. Notably, TRP exhibits a significantly reduced ulcerogenic potential relative to conventional NSAIDs and lacks detectable adverse cardiovascular effects. Despite these promising findings, the potential impact of TRP on the central nervous system, particularly on immunocompetent microglial cells—the resident immune cells of the CNS—remains unexplored.

AIM: The present study aimed to investigate the effects of TRP on selected markers of microglial activity under basal conditions and following lipopolysaccharide (LPS) stimulation.

METHODS: Primary microglial cultures were derived from 1–2-day-old C57BL/6J mouse pups. TRP was added at concentrations ranging from 0.1 to 100 μM for 24 hours. The concentration of the pro-inflammatory cytokine interleukin-1β (IL-1β) was quantified using ELISA. Cytotoxicity was assessed via the lactate dehydrogenase (LDH) release assay. Nitric oxide (NO) production was measured using the Griess reagent.

RESULTS: Exposure to TRP at 10 μM significantly reduced LPS-induced microglial cell death, as evidenced by decreased LDH release. Moreover, LPS stimulation led to an upregulation of NO and IL-1β production, both of which were attenuated by TRP administration at the same concentration.

CONCLUSION: These findings suggest that Tryptamide modulates microglial activation by attenuating pro-inflammatory responses and protecting against cell death. The compound's ability to downregulate neuroinflammatory mediators positions it as a promising candidate for further investigation in the context of neuroimmune dysregulation.

The study was supported by a programme coordinated by the Medical Research Agency, co-financed by the European Union under the NextGeneration EU initiative, within the framework of the National Recovery Plan, Component D, Investment D3.1.1 (project no.

2024/ABM

Optimization of compound kinetics as a way to improve pharmacological efficacy of serotonin receptor ligands

Szymon Kordylewski, Kinga Kurowska, Ryszard Bugno, Grzegorz Satała, Krystyna Nędza, Sabina Podlewska

 Department of Medicinal Chemistry,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

In recent years, residence time has gained significant attention as a potential factor driving pharmacological effects of drugs. However, despite numerous studies, the exact role of residence time and the factors that influence this phenomenon remain poorly understood.

In this project, we aim to comprehensively investigate the molecular determinants governing the formation and stability of ligand-protein complexes, focusing on residence time for ligands of serotonin receptors 5-HT2A.

Our approach integrates in silico examination, organic synthesis and in vitro studies to identify the molecular factors influencing ligand binding and the time it remains bound to the target. In the initial phase, we concentrated on well-characterized reference ligand, ritanserin, with a reported residence time of 160 minutes. Through structural modifications of this 5-HT2AR antagonist and the synthesis of new derivatives, we obtained a diverse set of compounds with varying activity and kinetic properties at the 5-HT2A receptor.

Further, we employed an advanced enhanced sampling methodologies to capture unbinding events in molecular dynamics simulations and perform structure–kinetics relationship (SKR) analyses to systematically elucidate the molecular determinants of dissociation kinetics. Random acceleration molecular dynamics (RAMD) simulations were employed to induce ligand unbinding via stochastic forces, enabling sampling of multiple dissociation pathways and estimation of relative residence time trends. The most probable unbinding pathway was further refined using metadynamics (MetaD).

The unbinding paths obtained via computational studies consistently indicated that the dissociation process is initiated with the disruption of key interactions with Asp3.32, Phe6.51, and F6.52. In the case of SK-125, which exhibited the longest residence time, additional stabilizing contacts were observed with V7.38 and Y2.68 following exit from the orthosteric binding pocket—interactions absent in the shorter-residence-time ligands. Furthermore, SK-125 maintained a greater number of transient stabilizing interactions throughout the dissociation process, suggesting a potential mechanistic basis for its prolonged target engagement.

The obtained results enabled us to design a library of further ritanserin derivatives, which underwent in silico studies and are now being synthesized to confirm the observed SKR dependencies and provide new insights into the structural features governing the duration of ligand-5-HT2AR complexes.

Acknowledgments
The study was supported by the grant OPUS 2023/49/B/NZ7/03340 financed by the National Science Centre, Poland (https://www.ncn.gov.pl).

Antidepressant and anxiolytic effects of psilocybin in animal models of depression

Krystyna Gołembiowska, Agnieszka Bysiek, Izabela Szpręgiel, Adam Wojtas, Marzena Maćkowiak, Agnieszka Wawrzczak-Bargieła, Weronika Kumorek

Department of Pharmacology,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Psilocybin belongs to the natural origin tryptamine class of psychedelics. It is already recognized as a putative antidepressant and anxiolytic drug that is shown in a number of clinical trials. However, its pharmacology and neurobiological mechanism is not well understood.  In the present work we studied the effect of psilocybin on rat behavior in animals subjected to chronic unpredictable mild stress (CUMS). Psilocybin administered twice at the dose of 0.6 mg/kg at a weekly interval reversed anhedonia in rats, showed anxiolytic effect in Light/Dark Box (LDB) and Elevated Plus Maze (EPM) tests. It also affected animal’s activity in the open field (OF) test and produced an antidepressant effect in the Forced Swim Test (FST). Furthermore, psilocybin increased proliferation and neuron development in the rat’s hippocampus. The data show that psilocybin as agonist of serotonin 5-HT2A and 5-HT1A receptors is able to induce neuroplastic changes in the brain resulting in reversal of depressive-like symptoms in CUMS animal model of depression.

Acknowledgemets: this research was funded by National Science Centre grant no. 2020/37/B/NZ7/03753 given to Krystyna Gołembiowska     

Shaping Efficacy of Opioid Receptors Ligands: Insights from Molecular Dynamics Simulations

Kinga Kurowska, Sabina Podlewska

 Department of Medicinal Chemistry,

Maj Institute of Pharmacology Polish Academy of Sciences,

Krakow, Poland

Opioid receptors, especially the μ-opioid receptor (MOR), play a central role in pain management. Traditional opioids are effective but cause side effects like tolerance and dependence. Recent research on biased agonism—where MOR ligands favor G protein signaling over β-arrestin pathways—offers a way to separate pain relief from harmful effects. On the other hand, there are studies which highlight the role of ligand-binding kinetics in signaling bias. Ligands with prolonged residence time (RT) are supposed to stabilize specific receptor conformations that contribute to particular signaling outcomes. This study aimed to explore the relationship between ligand-protein contacts (via MD simulations), kinetics, and biased signaling to identify molecular determinants of MOR complex stability.

We focused on a subset of seven MOR ligands with experimentally determined RT, exhibiting diverse signaling profiles, ranging from G protein-biased to mixed pathway engagement. Each ligand was docked to three MOR crystal structures, and the resulting complexes were subjected to MD simulations.

A detailed analysis of ligand–protein contact patterns across all simulations was conducted, with particular emphasis on their frequency and dynamics.

Two main interaction patterns were observed, involving contacts with residues D3.32 and Y7.42, according to the Ballesteros–Weinstein numbering scheme.

Although all ligands formed an ionic interaction with D3.32 in static docking models, three types of interactions were observed during the MD simulations: ionic bonds, hydrogen bonds, and water-mediated bridges. For Buprenorphine, which exhibited the longest RT (62.5 minutes), ionic interaction with D3.32 was predominant. In the case of Alvimopan (RT = 43.478 minutes), hydrogen bonding was the dominant contact  type, whereas for the remaining ligands with RTbelow 4 minutes, water-mediated bridges were prevalent. Thus, direct interactions with D3.32 (especially ionic bonds) correlated with significantly prolonged RT compared to interactions mediated by water molecules. Furthermore, the stronger nature of ionic bonds compared to hydrogen bonds likely contributes to the observed differences in RT.

The results obtained within this study have been used to the design of MOR ligands which are supposed to be characterized by prolonged RT which are currently being synthesized. In general, molecular determinants of prolonged RT of MOR ligands will be of great assistance when designing MOR agents and tuning their RT and signaling pathways.

Acknowledgments

The study was supported by the grant OPUS 2023/49/B/NZ7/03340 financed by the National Science Centre, Poland (https://www.ncn.gov.pl).

We welcome all researchers interested in affective-cognitive bias research, using diverse approaches in both animal and human studies.

Additionally, we extend a warm invitation to behavioral neuroscientists, animal welfare researchers, psychopharmacologists, experimental psychologists, and psychiatrists, as well as anyone engaged in related fields who wishes to contribute to this interdisciplinary discussion.