Biology subjects

Lespine, L.-F.

Publications and source records attributed to Lespine, L.-F..

4 recordsLinked to original sources

bioRxiv2019

Neuro-functional correlates of protective effects of wheel-running exercise against cocaine locomotor sensitization in mice: a fallypride microPET study

Wheel-running exercise in laboratory rodents (animal model useful to study the neurobiology of aerobic exercise) decreases behavioral markers of vulnerability to addictive properties of various drugs of abuse including cocaine. However, neurobiological mechanisms underpinning this protective effect are far from being fully characterized and understood. Here, 28-day-old female C57BL/6J mice were housed with (n=48) or without (n=48) a running wheel for 6 weeks before being tested for acute locomotor responsiveness and initiation of locomotor sensitization to intraperitoneal injections of 8 mg/kg cocaine. The long-term expression of sensitization took place 3 weeks after the last session. On the day after, all mice underwent a microPET imaging session with [18F]fallypride radiotracer (dopamine 2/3 receptor (D2/3R) antagonist). Exercised mice were less sensitive to acute and sensitized cocaine hyperlocomotor effects, such attenuation being particularly well-marked for long-term expression of sensitization ({eta}2p = 0.262). Additionally, we found that chronic administrations of cocaine was associated with a clear-cut increase of [18F]fallypride binding potential in mouse striatum ({eta}2p = 0.170), presumably reflecting an increase in postsynaptic D2/3R density in this region. Finally, we found evidence that wheel-running exercise was associated with a moderate decrease in D2/3R density in striatum ({eta}2p = 0.075), a mechanism that might contribute to protective properties of such form of exercise against drugs of abuse vulnerability.

neuroscience↗

bioRxiv2018

Wheel-running exercise before and during gestation against acute and sensitized cocaine psychomotor-activation in offspring

While animal research has consistently reported preventive effects of exercise against drug abuse vulnerability, little is known about the influence of the developmental stage during which exercise is displayed on addictive drugs responsiveness. This study aimed to determine whether prenatal exercise could attenuate acute cocaine reactivity and psychomotor sensitization in youth offspring. We used a split-plot factorial design where C57BL/6J females were randomly assigned into sedentary or exercised (wheel-running) conditions before and during gestation, the wheels being removed on gestational day 18. Offspring were weaned, gendered and individually housed on 24-28 days old. At 38-42 days old, they were tested for their acute psychomotor responsiveness to 8 mg/kg cocaine and their initiation of sensitization over 8 additional once-daily administrations, the long-term expression of sensitization occurring 30 days later. Adolescent females born from exercised mothers were much less responsive to the acute psychomotor-stimulating effect of cocaine than those born from sedentary mothers (d = 0.75, p = .02), whereas there was no evidence for such a difference in males (d = 0.34, p = .17). However, we did not find sizeable attenuating effects of prenatal exercise on the initiation and the long-term expression of the psychomotor-activating effect of cocaine, in either sex (Cohens ds varying from -0.23 to 0.39). These results suggest that prenatal exercise may induce initial protection against cocaine responsiveness in youth females, a finding that warrants further research.

neuroscience↗

bioRxiv2018

Wheel-running exercise during adolescence may not convincingly impact cocaine conditioned place preference in male C57BL/6J mice

Wheel-running in rodents can mitigate addiction-related effects of drugs of abuse like cocaine. However, experiments using conditioned place preference (CPP) are conflicting, warranting further studies. Our purpose was to test whether wheel-running during adolescence could impact the formation and long-term retention of CPP to cocaine in mice. Male C57BL/6J mice were individually housed either with (n=32) or without (n=32) a running wheel from the age of 35 days. Behavioral testing began 3 weeks after such housing, mice underwent a baseline session followed by 10 once-daily conditioning sessions receiving peritoneal injections of 10 mg/kg cocaine and saline on alternate days (n=16), control mice receiving saline every day (n=16). One and 21 days after the last conditioning session, they were tested for CPP. Both groups exhibited comparable well-marked cocaine-induced CPP in both post-conditioning tests resulting in a negligible interaction between housing and the pharmacological treatment ({eta}{superscript 2}p < 0.01). These results, along with the discrepancy found in the literature, question the nature (and the robustness) of the effects that exercise induces on CPP to cocaine.

neuroscience↗

bioRxiv2017

Evidence for a long-term protection of wheel-running exercise against cocaine psychomotor sensitization in adolescent but not in young adult mice

Rodents housed with a running wheel can exhibit attenuated cocaine seeking and cocaine-induced psychomotor activation. However, the longevity of the exercise anti-drug protection and the influence of the developmental stage during which exercise is displayed received little attention. Here, females and males C57BL/6J mice, aged 28 (adolescents) or 77 (young adults) days were housed with (n=56) or without (n=28) a running wheel. After 3 weeks in these conditions, half of the exercised mice were deprived of their wheel (n=28) whereas the other half and the sedentary mice (no wheel) were kept in their respective environments throughout experimentation. After 3 additional weeks, mice were tested for initiation of psychomotor sensitization to 9 once-daily intraperitoneal injections of 8 mg/kg cocaine (following 2 drug-free test sessions). The expression of sensitization was assessed on a single test session 30 days after the last sensitizing cocaine injection. Continuously exercised mice (wheel throughout experimentation) were less responsive to the initiation and the expression of cocaine effects, regardless of the gender and the developmental period during which exercise was introduced. Wheel-running during adolescence attenuated in later life the initiation and the expression of sensitization in females and only its expression in males. In adult females and males, previously-exercised and sedentary mice exhibited indiscernible levels of initiation and expression of sensitization. Thus, the likelihood of the long-term protection of exercise against cocaine vulnerability may depend not only on the gender but also and especially on the period of life in which exercise took place.

neuroscience↗