Evidence of melatonin involvement in pindolol-induced suppression of REM sleep

Summary.

The effects of pindolol, melatonin, and the melatonin receptor agonist agomelatine were studied in rats implanted for chronic sleep procedures. Administration of pindolol (1.0–4.0 mg/kg) during the light phase induced a significant reduction of rapid-eye-movement sleep (REMS) and an increase of waking (W). In the rats recorded after receiving 1.0–6.0 mg/kg melatonin no significant differences were found in sleep or W compared with controls. Agomelatine (1.0–6.0 mg/kg) induced a significant increase of light sleep during the first 3 h of the recording period. Pretreatment with melatonin partly prevented the pindolol-induced suppression of REMS. However, agomelatine was ineffective in this respect. Overall, these data suggest that the decreased production of melatonin could play a role in REMS suppression related to pindolol administration.