Cell penetrating PNA constructs regulate galanin receptor levels and modify pain transmission in vivo

Peptide nucleic acids (PNAs) form stable and tight complexes with complementary DNA and/or RNA and would be promising antisense reagents if their cellular delivery could be improved. We show that a 21-mer PNA, complementary to the human Galanin receptor type 1 mRNA, coupled to the cellular transporter peptides, transportan or pAntennapedia(43-58), is efficiently taken up into Bowes cells where they block the expression of Galanin receptors. In rat, the intrathecal administration of the peptide-PNA construct results in a decrease in Galanin binding in the dorsal horn. The decrease in binding results in the inability of Galanin to inhibit the C fibers stimulation-induced facilitation of the rat flexor reflex, demonstrating that peptide-PNA constructs act in vivo to suppress expression of functional Galanin receptors.