B-list occasionally spoken about is going round (7)

Chemical neurotransmitter – in a moped (anag) (8)8 Threat to informer? (4,4,3,4)15 Youth is speaking about another: ‘Dickhead!’ (5,4)9 Bird once on Mauritius (4)4 Attempts – what Vlad the Impaler does (5)5 ‘The git-go’ (5)5 Horrendously per-millilitre expensive office supply (5)5