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Dynorphin-immunoreactive neurons in the rat nucleus accumbens: ultrastructure and synaptic input from terminals containing substance P and/or dynorphin.
J Comp Neurol. 1995 Jan 02; 351(1):117-33.JC

Abstract

The endogenous opioid peptide dynorphin is enriched in neurons in the nucleus accumbens, for which coexistence and synaptic interactions with substance P have been postulated. We examined the immunogold-silver localization of dynorphin and immunoperoxidase labeling for substance P in single coronal sections through the core subregion of the nucleus accumbens of acrolein-fixed rat brain tissue. Dynorphin-immunoreactive somata were more prevalent than substance P-containing neurons throughout the region sampled for ultrastructural analysis. Dynorphin-labeled cells were spherical, contained unindented nuclei, and were closely apposed to other somata and dendrites, some of which also contained dynorphin immunoreactivity. The appositions were characterized by the absence of glial processes and contiguous contacts between the plasma membranes. Smooth endoplasmic reticulum and coated vesicles could also be identified in the cytoplasms on either side of the somatic or dendritic appositions. The dynorphin somata and dendrites received synaptic input from numerous unlabeled as well as dynorphin- and/or substance P-labeled axon terminals. Both types of terminals were morphologically similar in their content of small and large dense core vesicles and their formation of mainly symmetric synaptic specializations. In addition to dynorphin-immunoreactive targets, numerous dynorphin- and substance P-labeled terminals also formed synapses with unlabeled somata and dendrites. In some cases, terminals separately labeled for dynorphin and substance P converged on common targets with or without detectable dynorphin immunoreactivity. Terminals colocalizing both peptides were also found to synapse on unlabeled or dynorphin-labeled somata and dendrites. Additionally, presynaptic interactions were suggested by close appositions between dynorphin- and/or substance P-labeled terminals and other terminals that were unlabeled, dynorphin labeled, or substance P labeled. These results provide morphological data suggesting nonsynaptic communication between dynorphin-immunoreactive neurons and other neurons possibly mediated through receptive sites or second messengers associated with smooth endoplasmic reticulum in the nucleus accumbens. They also indicate that, in this region, 1) the activity of dynorphin neurons may be dependent on activation of autoreceptors for dynorphin as well as substance P and 2) additional neurons lacking dynorphin immunoreactivity are most likely inhibited (symmetric junctions) by terminals containing either one or both peptides. The findings may have implications for motor and analgesic responses to aversive tonic pain transmitted through dynorphin and substance P pathways within the nucleus accumbens.

Authors+Show Affiliations

Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

7534773

Citation

Van Bockstaele, E J., et al. "Dynorphin-immunoreactive Neurons in the Rat Nucleus Accumbens: Ultrastructure and Synaptic Input From Terminals Containing Substance P And/or Dynorphin." The Journal of Comparative Neurology, vol. 351, no. 1, 1995, pp. 117-33.
Van Bockstaele EJ, Gracy KN, Pickel VM. Dynorphin-immunoreactive neurons in the rat nucleus accumbens: ultrastructure and synaptic input from terminals containing substance P and/or dynorphin. J Comp Neurol. 1995;351(1):117-33.
Van Bockstaele, E. J., Gracy, K. N., & Pickel, V. M. (1995). Dynorphin-immunoreactive neurons in the rat nucleus accumbens: ultrastructure and synaptic input from terminals containing substance P and/or dynorphin. The Journal of Comparative Neurology, 351(1), 117-33.
Van Bockstaele EJ, Gracy KN, Pickel VM. Dynorphin-immunoreactive Neurons in the Rat Nucleus Accumbens: Ultrastructure and Synaptic Input From Terminals Containing Substance P And/or Dynorphin. J Comp Neurol. 1995 Jan 2;351(1):117-33. PubMed PMID: 7534773.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dynorphin-immunoreactive neurons in the rat nucleus accumbens: ultrastructure and synaptic input from terminals containing substance P and/or dynorphin. AU - Van Bockstaele,E J, AU - Gracy,K N, AU - Pickel,V M, PY - 1995/1/2/pubmed PY - 1995/1/2/medline PY - 1995/1/2/entrez SP - 117 EP - 33 JF - The Journal of comparative neurology JO - J. Comp. Neurol. VL - 351 IS - 1 N2 - The endogenous opioid peptide dynorphin is enriched in neurons in the nucleus accumbens, for which coexistence and synaptic interactions with substance P have been postulated. We examined the immunogold-silver localization of dynorphin and immunoperoxidase labeling for substance P in single coronal sections through the core subregion of the nucleus accumbens of acrolein-fixed rat brain tissue. Dynorphin-immunoreactive somata were more prevalent than substance P-containing neurons throughout the region sampled for ultrastructural analysis. Dynorphin-labeled cells were spherical, contained unindented nuclei, and were closely apposed to other somata and dendrites, some of which also contained dynorphin immunoreactivity. The appositions were characterized by the absence of glial processes and contiguous contacts between the plasma membranes. Smooth endoplasmic reticulum and coated vesicles could also be identified in the cytoplasms on either side of the somatic or dendritic appositions. The dynorphin somata and dendrites received synaptic input from numerous unlabeled as well as dynorphin- and/or substance P-labeled axon terminals. Both types of terminals were morphologically similar in their content of small and large dense core vesicles and their formation of mainly symmetric synaptic specializations. In addition to dynorphin-immunoreactive targets, numerous dynorphin- and substance P-labeled terminals also formed synapses with unlabeled somata and dendrites. In some cases, terminals separately labeled for dynorphin and substance P converged on common targets with or without detectable dynorphin immunoreactivity. Terminals colocalizing both peptides were also found to synapse on unlabeled or dynorphin-labeled somata and dendrites. Additionally, presynaptic interactions were suggested by close appositions between dynorphin- and/or substance P-labeled terminals and other terminals that were unlabeled, dynorphin labeled, or substance P labeled. These results provide morphological data suggesting nonsynaptic communication between dynorphin-immunoreactive neurons and other neurons possibly mediated through receptive sites or second messengers associated with smooth endoplasmic reticulum in the nucleus accumbens. They also indicate that, in this region, 1) the activity of dynorphin neurons may be dependent on activation of autoreceptors for dynorphin as well as substance P and 2) additional neurons lacking dynorphin immunoreactivity are most likely inhibited (symmetric junctions) by terminals containing either one or both peptides. The findings may have implications for motor and analgesic responses to aversive tonic pain transmitted through dynorphin and substance P pathways within the nucleus accumbens. SN - 0021-9967 UR - https://www.unboundmedicine.com/medline/citation/7534773/Dynorphin_immunoreactive_neurons_in_the_rat_nucleus_accumbens:_ultrastructure_and_synaptic_input_from_terminals_containing_substance_P_and/or_dynorphin_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0021-9967&date=1995&volume=351&issue=1&spage=117 DB - PRIME DP - Unbound Medicine ER -