The neuropeptide Y Y1 receptor is a somatic receptor on dorsal root ganglion neurons and a postsynaptic receptor on somatostatin dorsal horn neurons

Abstract

Using indirect immunofluorescence, neuropeptide Y Y1 receptor (Y1 receptor)-like immunoreactivity (LI) was localized close to the plasmalemma of small neurons in lumbar dorsal root ganglia (DRGs) and neurons in the inner lamina II of the lumbar spinal cord of the rat. Using confocal microscopy, colocalization of Y1 receptor-LI and transferrin receptor-LI, a marker for endosomes and coated vesicles, was observed in dot-like structures along the plasmalemma. Under the electron microscope, Y1 receptor-LI was localized in coated vesicles and endosomes, in the membrane of tubular cisternae, sometimes connected to multivesicular bodies, and in the plasmalemma. These complex distribution patterns may reflect receptor turnover and internalization processes. In the lamina II of the spinal dorsal horn, Y1 receptor-LI was localized in the plasmalemma of neurons without any apparent association with paramembrane structures, as described above for the DRG neurons. Many dendrites were Y1 receptor-positive, and some of them made synaptic contacts with unstained axonal terminals. In general, Y1 receptor-LI was localized in the membrane outside the postsynaptic density. Double-immunofluorescence staining showed that most Y1 receptor-immunoreactive neurons in lamina II contained somatostatin-LI. Both in DRG and dorsal horn neurons, the Y1 receptor thus seems to represent a postjunctional/postsynaptic receptor.

Nerve injury-induced tactile allodynia is present in the absence of FOS labeling in retrogradely labeled post-synaptic dorsal column neurons

“…The identified PSDC profiles did not co-express fluorescent labeling for parvalbumin, calbindin D, CGRP, substance P, PKCg, NPY and galanin or for the MOR, Y1, NK1 or P2X 3 receptors in either group of animals. The profile found in the present study is consistent with previous observations (Zhang et al 1999;Ossipov et al 2002;Todd, 2002;Gardell et al 2003). Earlier electrophysiologic studies indicated that transmission of visceral nociception to the n. gracilis is mediated through the PSDC neurons (Palecek et al, 2003;Al-Chaer et al 1996a).…”

Opioid-Like Actions of Neuropeptide Y in Rat Substantia Gelatinosa: Y1 Suppression of Inhibition and Y2 Suppression of Excitation

“…In some cells, NPY and [F7, P34]NPY also decreased mIPSC amplitude distributions, suggesting an additional postsynaptic action. This is consistent with reports that Y1 receptors are localized to the dendrites of somatostatin (SST)-positive dorsal horn neurons (Zhang et al 1994a(Zhang et al , 1999. SST-containing neurons in the dorsal horn represent a morphologically heterogeneous population that is composed of both stalked and islet cells (Ribeiro-da-Silva and Cuello 1990;Todd and Spike 1993), some of which are thought to be excitatory interneurons (Todd and McKenzie 1989;Spike and Todd 1992).…”

“…This is consistent with the presence of Y1 receptors on presynaptic inhibitory terminals and likely also postsynaptically on SG neurons. (Zhang et al 1994a(Zhang et al , 1999. FIG. 4.…”

Monitoring of the internalization of neuropeptide Y on neuroblastoma cell line SK‐N‐MC

“…Using immunofluorescence, confocal laser microscopy, and electron microscopy, Zhang et al [22] made similar observations concerning the distribution of the Y1 receptor on ganglion neurons. By colocalization of the Y1 receptor and the transferrin receptor in dot-like structures along the plasmalemma and a complex distribution pattern in the cells, they concluded on receptor turnover and internalization.…”