Chronic Sleep Deprivation Blocks Voluntary Morphine Consumption but Not Conditioned Place Preference in Mice

Area of Science:

• Neuroscience
• Sleep Science
• Addiction Research

Background:

• The opioid epidemic causes over 100,000 deaths annually.
• Poor sleep exacerbates pain sensitivity, impulsivity, and negative affect, potentially worsening drug use.
• Opioid users experience disrupted sleep, a factor in relapse.

Purpose of the Study:

• To investigate the impact of chronic short sleep (CSS) on opioid reward.
• To explore the neurobiological mechanisms underlying the relationship between sleep loss and opioid use.

Main Methods:

• Utilized a mouse model of chronic short sleep (CSS) (<7 hours nightly).
• Assessed corticosterone levels, depressive-like behavior, and microglial activation (Iba1 expression) in the hypothalamus.
• Evaluated morphine preference using a 2-bottle choice test and morphine conditioned place preference (mCPP).

Main Results:

• CSS did not elevate corticosterone or depressive-like behavior after acute sleep deprivation.
• Four weeks of CSS increased hypothalamic Iba1 expression, indicating microglial activation.
• Mice exposed to CSS did not develop a preference for morphine in the 2-bottle choice test, unlike rested controls.
• Both groups showed similar morphine conditioned place preference (mCPP).

Conclusions:

• Recovery sleep following chronic sleep disruption reduces voluntary opioid intake.
• Conditioned reward associated with morphine is not affected by chronic short sleep or subsequent recovery sleep.
• These findings suggest distinct effects of sleep disruption on different aspects of opioid reward.