Notes insist worker gets sedative (10)
I believe the answer is:
depressant
'sedative' is the definition.
(I know that sedative can be written as depressant)
'notes insist worker' is the wordplay.
'notes' becomes 'de' (two musical notes).
'insist' becomes 'press' (I've seen this in another clue).
'worker' becomes 'ant' (worker is a type of ant).
'de'+'press'+'ant'='DEPRESSANT'
'gets' is the link.
(Other definitions for depressant that I've seen before include "Drug reducing nervous activity" , "Downer" , "reducing activity of vital functions" , "Sedative drug" , "Lowering spirits" .)