The relationship between cocaine self-administration and actigraphy-based measures of sleep in adult rhesus monkeys

The relationship between sleep and appetitive conditioning: A systematic review and meta-analysis

This systematic review and meta-analysis (PROSPERO registration animal/human studies: CRD42021234793/CRD42021234790) examined the relationship between sleep and appetitive conditioning. Inclusion criteria included: a) appetitive conditioning paradigm; b) measure of conditioning; c) sleep measurement and/or sleep loss; d) human and/etor non-human animal samples; and e) written in English. Searches of seven databases returned 3777 publications. The final sample consisted of 42 studies using primarily animal samples and involving food- and drug-related conditioning tasks. We found sleep loss disrupted appetitive conditioning of food rewards (p < 0.001) but potentiated appetitive conditioning of drug rewards (p < 0.001). Furthermore, sleep loss negatively impacted extinction learning irrespective of the reward type. Post-learning sleep was associated with increases in REM sleep (p = 0.02). Findings suggest sleep loss potentiates the impact of psychoactive substances in a manner likely to produce an increased risk of problematic substance use. In obese/overweight populations, sleep loss may be associated with deficits in the conditioning and extinction of reward-related behaviours. Further research should assess the relationship between sleep and appetitive conditioning in humans.

Sleep loss and addiction

Reducing sleep hours is a risk factor for developing cardiovascular, metabolic, and psychiatric disorders. Furthermore, previous studies have shown that reduction in sleep time is a factor that favors relapse in addicted patients. Additionally, animal models have demonstrated that both sleep restriction and sleep deprivation increase the preference for alcohol, methylphenidate, and the self-administration of cocaine. Therefore, the present review discusses current knowledge about the influence of sleep hours reduction on addictivebehaviors; likewise, we discuss the neuronal basis underlying the sleep reduction-addiction relationship, like the role of the orexin and dopaminergic system and neuronal plasticity (i.e., delta FosB expression). Potentially, chronic sleep restriction could increase brain vulnerability and promote addictive behavior.

Ecological and social pressures interfere with homeostatic sleep regulation in the wild

Sleep is fundamental to the health and fitness of all animals. The physiological importance of sleep is underscored by the central role of homeostasis in determining sleep investment – following periods of sleep deprivation, individuals experience longer and more intense sleep bouts. Yet, most sleep research has been conducted in highly controlled settings, removed from evolutionarily relevant contexts that may hinder the maintenance of sleep homeostasis. Using triaxial accelerometry and GPS to track the sleep patterns of a group of wild baboons (Papio anubis), we found that ecological and social pressures indeed interfere with homeostatic sleep regulation. Baboons sacrificed time spent sleeping when in less familiar locations and when sleeping in proximity to more group-mates, regardless of how long they had slept the prior night or how much they had physically exerted themselves the preceding day. Further, they did not appear to compensate for lost sleep via more intense sleep bouts. We found that the collective dynamics characteristic of social animal groups persist into the sleep period, as baboons exhibited synchronized patterns of waking throughout the night, particularly with nearby group-mates. Thus, for animals whose fitness depends critically on avoiding predation and developing social relationships, maintaining sleep homeostasis may be only secondary to remaining vigilant when sleeping in risky habitats and interacting with group-mates during the night. Our results highlight the importance of studying sleep in ecologically relevant contexts, where the adaptive function of sleep patterns directly reflects the complex trade-offs that have guided its evolution.

Interaction between cocaine use and sleep behavior: A comprehensive review of cocaine's disrupting influence on sleep behavior and sleep disruptions influence on reward seeking

Dopamine, orexin (hypocretin), and adenosine systems have dual roles in reward and sleep/arousal suggesting possible mechanisms whereby drugs of abuse may influence both reward and sleep/arousal. While considerable variability exists across studies, drugs of abuse such as cocaine induce an acute sleep loss followed by an immediate recovery pattern that is consistent with a normal response to loss of sleep. Under more chronic cocaine exposure conditions, an abnormal recovery pattern is expressed that includes a retention of sleep disturbance under withdrawal and into abstinence conditions. Conversely, experimentally induced sleep disturbance can increase cocaine seeking. Thus, complementary, sleep-related therapeutic approaches may deserve further consideration along with development of non-human models to better characterize sleep disturbance-reward seeking interactions across drug experience.

Sleep Disturbance and Hyperactivity Detected by Actigraphy in Rats with Allergic Rhinitis or Attention-Deficit Hyperactivity Disorder

Actigraphy is an easy and noninvasive method used to monitor human ultradian cycles. However, to our knowledge, it has been not applied to experiments with rodents. Therefore, using actigraphy, we assessed the ultradian cycles and behavior of rats. Rats with or without allergic rhinitis wore an actigraphy device, and triaxial acceleration was recorded. The counts that represent physical activity were lower from 8:00 to 20:00 than those from 20:00 to 8:00 in control rats, suggesting that their sleep phase was from 8:00 to 20:00 and their awake phase from 20:00 to 8:00. The counts from 8:00 to 10:00 were significantly higher in allergic rhinitis rats than in control rats (p < 0.01), suggesting the presence of difficulty with sleep induction in rats with allergic rhinitis. The counts from 18:00 to 20:00 were also significantly higher in allergic rhinitis rats than in control rats (p < 0.05), suggesting the presence of early awakening in rats with allergic rhinitis. Moreover, the counts were significantly higher in allergic rhinitis rats than in control rats from 20:00 to 8:00. These results suggest that rats with allergic rhinitis experienced hyperactivity disorder during the daytime. Additionally, hyperreactivity and difficulty with sleep induction were observed in 6-hydroxydopamine-lesioned rats, an animal model of attention-deficit hyperactivity disorder. This study shows for the first time that actigraphy can be successfully used for behavioral analysis in rodents. These rat models could be useful for analyzing the mechanisms involved in sleep disturbances and hyperactivity disorder.

Dose response of acute cocaine on sleep/waking behavior in mice

Chronic cocaine use has been associated with sleep disturbances, both during active use periods and during withdrawal and abstinence. Acute cocaine also increases waking at the expense of slow wave sleep and Rapid Eye Movement in non-human subjects. However, the effects of acute cocaine on sleep/waking activity in mice, a rodent model commonly used in both sleep and addiction research due to its high genetic tractability, has yet to be investigated. Sleep/waking activity was measured via polysomnography following IP administration of three doses of cocaine (3.6, 9.6, 18 mg/kg) and vehicle control in male C57BL/6 mice. Cocaine dose-dependently increased sleep latency, increased waking time and increased fast EEG activity within waking. Increases in waking occurred primarily during the first hour following injection, followed by rebound SWS sleep. Sleep/waking activity normalized within a 24-hour period. As with humans and other rodents, cocaine dose dependently reduces sleep in a wildtype strain of mice commonly used in reward and addiction research.

Altered activity-based sleep measures in rhesus monkeys following cocaine self-administration and abstinence

BACKGROUND

Impairments in sleep and cognitive function have been observed in patients with substance abuse disorders and may be potential factors contributing to drug relapse. In addition, sleep disruption may itself contribute to cognitive deficits. In the present study we examined the impact of prolonged cocaine self-administration and abstinence on actigraphy-based measures of night-time activity in rhesus macaques as an inferential measure of sleep, and determined whether sleep-efficiency correlated with cognitive impairments in the same subjects on drug free days.

METHODS

Actigraphy data was obtained from a group of rhesus macaques intravenously self-administering cocaine (n=6) and a control group (n=5). Periods were evaluated during which the mean cumulative doses of cocaine were 3.0+0.0 and 4.5+0.2mg/kg/day for 4days (Tuesday-Thursday) each week.

RESULTS

Actigraphy-based sleep efficiency decreased during days of cocaine self-administration in a dose-dependent manner. Consistent with this observation, sleep became more fragmented. Activity-based sleep efficiency normalized during the weekend without cocaine prior to cognitive assessment on Monday. The magnitude of activity-based sleep disruption during self-administration did not correlate with the level of cognitive impairment on drug free days. With continued self-administration, the impact of cocaine on activity-based sleep efficiency declined indicating the development of tolerance.

CONCLUSIONS

Cocaine self-administration disrupted sleep efficiency in rhesus macaques as measured by actigraphy, but normalized quickly in the absence of cocaine. The cognitive impairment observed on drug free days was unlikely to be related to disruption of the nightly activity patterns on days of cocaine self-administration.

Evaluation of the Reinforcing Effect of Quetiapine, Alone and in Combination with Cocaine, in Rhesus Monkeys

There are several case reports of nonmedicinal quetiapine abuse, yet there are very limited preclinical studies investigating quetiapine self-administration. The goal of this study was to investigate the reinforcing effects of quetiapine alone and in combination with intravenous cocaine in monkeys. In experiment 1, cocaine-experienced female monkeys (N = 4) responded under a fixed-ratio (FR) 30 schedule of food reinforcement (1.0-g banana-flavored pellets), and when responding was stable, quetiapine (0.003-0.1 mg/kg per injection) or saline was substituted for a minimum of five sessions; there was a return to food-maintained responding between doses. Next, monkeys were treated with quetiapine (25 mg, by mouth, twice a day) for approximately 30 days, and then the quetiapine self-administration dose-response curve was redetermined. In experiment 2, male monkeys (N = 6) self-administered cocaine under a concurrent FR schedule with food reinforcement (three food pellets) as the alternative to cocaine (0.003-0.3 mg/kg per injection) presentation. Once choice responding was stable, the effects of adding quetiapine (0.03 or 0.1 mg/kg per injection) to the cocaine solution were examined. In experiment 1, quetiapine did not function as a reinforcer, and chronic quetiapine treatment did not alter these effects. In experiment 2, cocaine choice increased in a dose-dependent fashion. The addition of quetiapine to cocaine resulted in increases in low-dose cocaine choice and number of cocaine injections in four monkeys, while not affecting high-dose cocaine preference. Thus, although quetiapine alone does not have abuse potential, there was evidence of enhancement of the reinforcing potency of cocaine. These results suggest that the use of quetiapine in cocaine-addicted patients should be monitored.

Effects of quetiapine treatment on cocaine self-administration and behavioral indices of sleep in adult rhesus monkeys

RATIONALE

Clinical literature suggests a link between substance abuse and sleep disturbances. Quetiapine, an atypical antipsychotic, has shown efficacy in treating sleep disturbances, with clinical studies showing promise for quetiapine as a treatment for cocaine abuse.

OBJECTIVE

The goal of this study was to examine the effects of quetiapine on cocaine self-administration and behavioral indices of sleep in monkeys.

METHODS

Seven adult male rhesus monkeys, fitted with Actical® activity monitors, were trained to respond under a choice paradigm of food (1.0-g pellets) and cocaine (0.003-0.3 mg/kg per injection) presentation. First, monkeys received acute pretreatment (45 min) with quetiapine (25-75 mg, p.o.) prior to choice sessions; three cocaine doses were studied in combination with quetiapine. Next, the effect of chronic (14-16 days) quetiapine treatment (25-250 mg, p.o., BID) was examined in combination with the lowest preferred cocaine dose (≥80 % cocaine choice). Behavioral indices of sleep, based on activity measures obtained during lights-out, were recorded throughout the study.

RESULTS

Acute quetiapine decreased cocaine choice in four of the seven monkeys. Chronic quetiapine treatment resulted in initial decreases in cocaine choice, but tolerance developed to these effects. Acute doses of quetiapine did not improve sleep efficiency the following night nor did chronic quetiapine. The first night after discontinuing quetiapine treatment resulted in significant decreases in sleep efficiency and increases in nighttime activity.

CONCLUSIONS

These findings do not offer support for the use of quetiapine as a monotherapy for treatment of cocaine abuse nor as an adjunct therapy to treat sleep disturbances associated with stimulant abuse.