Circadian clock genes: Effects on dopamine, reward and addiction

Abstract

Addiction is a widespread public health issue with social and economic ramifications. Substance abuse disorders are often accompanied by disruptions in circadian rhythms including sleep/wake cycles, which can exacerbate symptoms of addiction and dependence. Additionally, genetic disturbance of circadian molecular mechanisms can predispose some individuals to substance abuse disorders. In this review, we will discuss how circadian genes can regulate midbrain dopaminergic activity and subsequently, drug intake and reward. We will also suggest future directions for research on circadian genes and drugs of abuse.

Ethylphenidate: availability, patterns of use, and acute effects of this novel psychoactive substance

“…Twenty-four papers were not specifically included: 20 related to methylphenidate rather than ethylphenidate, 3 described ethylphenidate's use as an internal standard for measuring methylphenidate, and a further paper related to analytical identification of ethylphenidate [6,7,9,10,[12][13][14][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66].…”

“…It is an analogue of methylphenidate that has significantly greater dopaminergic selectivity, with a 16-fold greater affinity for the dopamine transporter than the noradrenaline transporter, as compared with methylphenidate [6]. This potentially increases the addiction potential of ethylphenidate [7].…”

A novel role for dopamine signaling in the pathogenesis of bone loss from the atypical antipsychotic drug risperidone in female mice

“…Dopamine is a highly expressed neurotransmitter that is involved in the regulation of diverse biological effects including reward, locomotor activity, cognition, hormone secretion, food intake and circadian rhythms [33,34]. Effects of dopamine are elicited via a family of G-protein coupled dopamine receptors (D1–5) which are expressed throughout the body (including in bone) and signal via distinct pathways [35].…”

Sleep and REM sleep behaviour disorder in Parkinson’s disease with impulse control disorder

“…On the one hand, nocturnal hyperactivity, as well as anxiety and depression, may contribute to poorer sleep in patients with ICDs. Also, it has been suggested that behavioural addiction in itself may influence sleep–wake cycle regulation by modulating the expression of the so-called clock genes 30. On the other hand, sleep deprivation may increase impulsivity and enhance emotional reactivity via a dysfunction of the prefrontal cortex–amygdala interactions 31 32.…”