Background: Cigarette smoking has shown to be associated with sleep disturbance, especially prolonged sleep onset latency (SOL). Cigarette smoking stimulates the release of dopamine (DA) and serotonin (5-HT), which might promote awakening and inhibit rapid eye movement sleep. Dopamine transporter (DAT) and serotonin transporter play a key role in the reuptake of DA and 5-HT from the synaptic cleft into presynaptic neurons. However, the relationship among cigarette smoking, sleep disturbance and neurotransmitters has never been investigated in human cerebrospinal fluid (CSF).
Methods: A total of 159 Chinese male subjects (81 active smokers and 78 non-smokers) who would undergo lumbar puncture before the surgery of anterior cruciate ligament reconstruction were recruited and 5mL-CSF samples were collected incidentally. CSF levels of DA, DAT, 5-HT, and serotonin transporter were measured using radioimmunoassay and ELISA. Sociodemographic data and the Pittsburgh Sleep Quality Index (PSQI) scale were collected before surgery.
Results: PSQI global scores, SOL, and CSF DA levels were significantly higher in active smokers compared to non-smokers (2.00 [1.00– 4.75] scores vs 4.00 [3.00– 6.00] scores, p = 0.001; 10.00 [5.00– 15.00] minutes vs 15.00 [10.00– 30.00] minutes, p = 0.002; 87.20 [82.31– 96.06]ng/mL vs 107.45 [92.78– 114.38] ng/mL, p < 0.001), while CSF DAT levels were significantly lower in active smokers (0.35 [0.31– 0.39] ng/mL vs 0.29 [0.26– 0.34] ng/mL, p < 0.001).
Conclusion: Cigarette smoking was indeed associated with sleep disturbance, shown by prolonged SOL, higher DA levels and lower DAT levels in CSF of active smokers.
Keywords: sleep, cigarette smoking, dopamine, cerebrospinal fluid