NK1 RECEPTOR EXPRESSION BY CHOLINERGIC INTERNEURONS IN HUMAN STRIATUM

NEUROKININ-1 (NK1) receptor expression in human striatum was analysed using the polymerase chain reaction. To determine whether cholinergic interneurones express this receptor, in situ hybridization histochemis try was then applied to caudate nucleus and putamen. Radioactive oligo nucleotide probes specific for choline acetyltransferase (ChAT) and NK 1 receptor mRNA were used on adjacent cryostat sections. All of the 16 0 identified neurones positive for ChAT were also labelled for NK1 rec eptor. Moreover, in the caudate nucleus, NK1 receptor mRNA was detecte d in a population of large neurones that were not cholinergic. These r esults are consistent with the hypothesis that NK1 receptor-mediated m echanisms are involved in the function of cholinergic interneurones. T his might be relevant to pharmacological or pathophysiological situati ons where substance P inputs are modified.