title: Immunocytochemical evidence for a serotoninergic innervation of dorsal column postsynaptic neurons in cat and monkey: light- and electron-microscopic observations.
abstract: Dorsal column postsynaptic neurons in the lumbosacral enlargements of cats and a monkey were retrogradely labeled by placing horseradish peroxidase on their severed axons in the thoracic dorsal columns. After visualizing the retrogradely-labeled neurons, the tissue was immunocytochemically stained with an antiserum directed against serotonin. Immunoreactive axonal varicosities contacted the perikarya and proximal dendrites of every retrogradely-labeled neuron examined in cat (mean 61 contacts/cell) and nearly every neuron in the monkey (mean 18 contacts/cell). Electron microscopy showed that the immunoreactive axonal varicosities contained pleomorphic (round to oval) agranular vesicles and formed symmetrical synapses on retrogradely-labeled neurons. It is concluded that dorsal column postsynaptic neurons are innervated directly by the brain stem's descending, serotoninergic system(s).
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure; D001933:Brain Stem / Q000033:anatomy & histology*; D002415:Cats; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D005727:Ganglia, Spinal / Q000033:anatomy & histology*; D007124:Immunoenzyme Techniques; D008252:Macaca fascicularis; D008297:Male; D008854:Microscopy, Electron; D012701:Serotonin / Q000378:metabolism*; D013569:Synapses / Q000648:ultrastructure
chemical_list: D012701:Serotonin