The invention provides a conjugate comprising (i) a selectivity agent which binds specifically to one or more neurotransmitter transporters selected from the group consisting of a dopamine transporter (DAT), serotonin transporter (SERT) or a norepinephrine transporter (NET) and (ii) a nucleic acid capable of specifically binding to a target molecule which is expressed in the same cell as the neurotransmitter transporter wherein said target molecule is &alpha-synuclein or the mRNA encoding &alpha-synuclein. The conjugates of the present invention are useful for the delivery of the nucleic acid to a cell of interest and thus, for the treatment of diseases which require a down-regulation of the protein encoded by the target nucleic acid as well as for the delivery of imaging agents to the cells for diagnostic purposes.
