Biology subjects

Jehl, J.

Publications and source records attributed to Jehl, J..

6 recordsLinked to original sources

bioRxiv2026

Focal drug uncaging for the precise control of endogenous nicotinic receptors in behaving mice

Nicotinic acetylcholine receptors shape diverse brain functions, including reward, aversion, and pain, but dissecting their roles in vivo requires drug delivery with spatiotemporal precision that conventional pharmacology cannot provide. Here we establish in vivo photopharmacology of endogenous nicotinic receptors: two complementary, highly-potent agonists, administered systemically in an inactive caged form, are photoreleased locally in target brain circuits of behaving wild-type mice. Despite irreversible photochemistry, photoactivation can be repeated over many trials on a minute timescale, for hours following a single injection. Local uncaging evokes circuit-specific dopamine release, drives place preference from the ventral tegmental area and aversion from the interpeduncular nucleus, and, in pain circuits, reveals a pronociceptive effect masked when the same agonists are given systemically. By controlling where and when nicotinic signaling acts, this approach exposes circuit-specific drug effects invisible to conventional pharmacology, and outlines a general strategy for on-demand control of endogenous receptors in vivo.

neuroscience↗

bioRxiv2026

Differential efficacy of α5IA in the Dp(16)1Yey mouse model of Down syndrome: implications for translational research

Cognitive impairments significantly impact the daily life of people with Down syndrome (DS). Overinhibition mediated by interneurons in the central nervous system was proposed as a key pathophysiological mechanism. Previous studies demonstrated cognitive rescue in the Ts65Dn mouse model using 5IA, a negative allosteric modulator of the 5 subunit-containing GABAA receptors. Here, we evaluated the effect of this drug in a mouse model carrying a more accurate duplication of the orthologous region to the human chromosome 21, namely the Dp(16)1Yey mouse model. First, we expanded the phenotypic characterization of Dp(16)1Yey mice using translationally more relevant behavioral tests. We confirmed spatial memory deficits in Dp(16)1Yey mice in the Barnes maze, and highlighted robust learning deficits in the pattern dissociation task and impairments in motor coordination. Next, we evaluated the effect of 5IA treatment on cognitive and motor performance. While 5IA treatment improved motor coordination in the Dp(16)1Yey mice, it failed to restore cognitive performance in the Barnes maze or in the pattern dissociation task. These findings could suggest divergent pathophysiological mechanisms between the Dp(16)1Yey and the Ts65Dn models. Potentially, it could explain the limited efficacy of similar pharmacological intervention in clinical trials for DS. Further preclinical studies should prioritize refined behavioral paradigms and probably the use of more complex DS models to enhance the translational potential of candidate therapies.

neuroscience↗

bioRxiv2024

Nicotine engages a VTA-NAc feedback loop to inhibit amygdala-projecting dopamine neurons and induce anxiety.

Nicotine activates ventral tegmental area (VTA) dopaminergic (DA) neurons projecting to the nucleus accumbens (NAc) to drive its reinforcing effects. Simultaneously, it inhibits those projecting to the amygdala (Amg) to mediate anxiety through a process that remains unknown. Here we show that NAc- and Amg-projecting DA neurons respond with similar polarities to ethanol and nicotine, suggesting a shared network-based mechanism underlying the inhibitory effect of these otherwise pharmacologically-distinct drugs. Selective activation of NAc-projecting DA neurons, using genetic or optogenetic strategies, produced inhibition of Amg-projecting DA neurons, through a GABAergic feedback loop. Furthermore, optogenetically silencing this feedback loop prevented nicotine from inducing both inhibition of DA neurons and anxiety-like behavior. Therefore, nicotine-induced inhibition of the VTA-Amg DA pathway results from a VTA-NAc inhibitory feedback loop, mediating anxiety.

neuroscience↗

bioRxiv2024

Dopamine reveals adaptive learning of actions representation

Flexible decision-making requires not only updating values, but redefining which features constitute an action in a given context. We recorded nucleus accumbens (NAc) dopamine release while mice navigated a three-target intracranial self-stimulation foraging task in which outcomes were evaluated under three distinct reward delivery rules. Despite a constant motor repertoire, dopamine transients reorganized across contingencies and generalized linear models revealed context-dependent dopamine signal reflecting action direction, recent outcome-history, or target identity. Reinforcement-learning model comparison showed that these signatures are best explained by distinct reward prediction errors (RPEs) defined over different state-action representations, rather than a single fixed model-free scheme. A single deep reinforcement-learning agent trained by temporal-difference learning, recapitulated both the rule-specific policies and the corresponding dopamine signature. These results identify NAc dopamine as a dynamic readout of representation learning, remapping prediction errors onto the task features that define successful action as contingencies change.

neuroscience↗

bioRxiv2023

The interpeduncular nucleus blunts the rewarding effect of nicotine

Nicotine, by stimulating ventral tegmental area (VTA) dopaminergic neurons, has a rewarding effect that drives tobacco consumption. In turn, the interpeduncular nucleus (IPN) is thought to become activated at high nicotine doses to restrict drug intake. However, the dynamics of the IPN response to nicotine and its impact on the rewarding effect of the drug remain unknown. To address this issue, we have developed a genetically-modified mouse model, in which a "suicide" antagonist of nicotinic acetylcholine receptors (nAChRs) selectively attaches to a designer {beta}4 nAChR subunit. By locally infusing this antagonist in the IPN, we achieved pharmacologically-specific and sustained antagonism of nAChRs containing the {beta}4 subunit. By combining this chemogenetic method with in vivo electrophysiology, we show that even at low doses, nicotine activates and inhibits two different populations of IPN neurons, and that {beta}4-containing nAChRs are only involved in the activation response. Furthermore, blocking the response to nicotine selectively in the IPN increased both the sensitivity of the VTA to the drug and its rewarding effect in a conditioned place preference paradigm. These findings indicate that the IPN is engaged across a large range of nicotine doses and acts as a regulatory brake on the nicotine reward circuit.

neuroscience↗

bioRxiv2021

Prolonged nicotine exposure reduces aversion to the drug in mice by altering nicotinic transmission in the interpeduncular nucleus.

Nicotine intake is likely to result from a balance between the rewarding and aversive properties of the drug, yet the individual differences in neural activity that control aversion to nicotine and their adaptation during the addiction process remain largely unknown. Using a two-bottle choice experiment, we observed a high heterogeneity in nicotine-drinking profiles in isogenic adult male mice, with about half of the mice persisting in consuming nicotine even at high concentrations, whereas the other half stopped consuming. We found that nicotine intake was negatively correlated with nicotine-evoked currents in the interpeduncular nucleus (IPN), and that prolonged exposure to nicotine, by weakening this response, decreased aversion to the drug, and hence boosted consumption. Lastly, using knock-out mice and local gene re-expression, we identified {beta}4-containing nicotinic acetylcholine receptors of IPN neurons as the molecular and cellular correlates of nicotine aversion. Collectively, our results identify the IPN as a substrate of individual variabilities and adaptations in nicotine consumption.

neuroscience↗