Prepro-neuropeptide Y mRNA and NPY binding sites in human inferior vagal ganglia.

The inferior vagal ganglia contain the cell bodies of centrally projecting vagal afferent neurones. Using in situ hybridization-histochemistry with a combination of two antisense neuropeptide Y (NPY) oligonucleotides, we have demonstrated that a population of human inferior vagal perikarya express mRNA encoding prepro-NPY, the precursor of NPY. In vitro receptor autoradiography, using both [125I]Bolton Hunter-NPY ([125I]BH-NPY, 15 pM) and [125I]peptide YY ([125I]PYY, 25 pM), enabled visualization of NPY binding sites. Competition binding with NPY (1 microM), PYY (1 microM) and [Leu31,Pro34]NPY (100 nM), suggest that both Y1 and Y2 receptor subtypes are present on human vagal afferent neurones. These observations suggest a potential role for NPY in neuromodulation of vagal transmission in humans.