Axons which take up [3H]serotonin are presynaptic to enkephalin immunoreactive neurons in cat dorsal horn.
Through combined ultrastructural localization of ENK immunoreactivity and [3H]5-HT uptake sites, it was found that 5-HT radiolabeled axons contact ENK immunoreactive cell bodies and small dendrites in the cat superficial dorsal horn. While some contacts displayed both pre- and postsynaptic specializations, the majority lacked a definitive synaptic cleft and postsynaptic density. These results suggest that 5-HT-containing axons, presumably derived from the medullary nucleus raphe magnus, directly influence spinal opiod antinociceptive activity.
D000344:Afferent Pathways / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001370:Axonal Transport; D002415:Cats; D003712:Dendrites / Q000378:metabolism; D004745:Enkephalins / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008526:Medulla Oblongata / Q000378:metabolism; D009619:Nociceptors / Q000378:metabolism; D011903:Raphe Nuclei / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*
D004745:Enkephalins; D012701:Serotonin