Inhibitory Interneurons That Express GFP in the PrP-GFP Mouse Spinal Cord Are Morphologically Heterogeneous, Innervated by Several Classes of Primary Afferent and Include Lamina I Projection Neurons among Their Postsynaptic Targets

摘要: The superficial dorsal horn of the spinal cord contains numerous inhibitory interneurons, which regulate transmission information perceived as touch, pain, or itch. Despite importance these cells, our understanding their roles in neuronal circuitry is limited by difficulty identifying functional populations. One group that has been identified and characterized consists cells mouse express green fluorescent protein (GFP) under control prion (PrP) promoter. Previous reports suggested PrP-GFP belonged to a single morphological class (central cells), received inputs exclusively from unmyelinated primary afferents, had axons remained lamina II. However, we recently reported expressed nitric oxide synthase (nNOS) and/or galanin, it shown nNOS-expressing are more diverse morphology synaptic connections. We therefore used combined electrophysiological, pharmacological, anatomical approach reexamine cells. provide evidence they morphologically (corresponding "unclassified" cells) receive input variety with convergence onto individual also show project into adjacent laminae target putative projection neurons I. This indicates involving complex than previously recognized, suggests likely have several distinct regulating flow somatosensory through horn.