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Cellular substrates for interactions between neurons containing phenylethanolamine N-methyltransferase and GABA in the nuclei of the solitary tracts.
J Comp Neurol. 1989 Aug 08; 286(2):243-59.JC

Abstract

Adrenaline and gamma-aminobutyric acid (GABA) have been implicated in autonomic functions involving the intermediate and caudal portions of the medial nuclei of the solitary tracts (m-NTS). We sought to determine whether there was a cellular basis for direct intracellular or synaptic interactions between these transmitters in neurons in the m-NTS of rat brain by using dual-labeling immunocytochemical methods. Light microscopy revealed immunoautoradiographic labeling for the adrenaline-synthesizing enzyme phenylethanolamine N-methyltransferase (PNMT) in perikarya and processes in close proximity to cells demonstrating peroxidase reaction product for GABA. Electron microscopy of the intermediate m-NTS at the level of the area postrema further established the localization of immunoautoradiographic and peroxidase labels for PNMT and GABA in common as well as separate perikarya and dendrites. All axon terminals were labeled separately for PNMT and GABA. The PNMT-labeled terminals formed both symmetric and asymmetric synapses, whereas the GABA-labeled terminals formed exclusively symmetric synapses. Twenty-four percent (n = 42) of the PNMT- and 39% (n = 128) of the GABA-labeled terminals formed synaptic junctions on unlabeled soma and dendrites. Occasionally both types of terminals converged on a common unlabeled dendrite and on GABA-labeled dendrites. Only 3% of the PNMT- and 12% of the GABA-containing terminals formed synapses on PNMT-labeled soma and dendrites, whereas 7% of each type formed synapses with GABA-labeled profiles. The remaining labeled terminals lacked synaptic relations within the sections examined. The autoradiographic results were confirmed and extended by means of immunogold labeling for PNMT in combination with peroxidase-antiperoxidase localization of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD). GAD-labeled terminals formed symmetric synapses with dendrites that were either unlabeled or contained low levels of PNMT (gold particles) or PNMT and GAD. We conclude that in caudal, more cardiovascular portions of the NTS, adrenaline and GABA may coexist, but they are more commonly detected in separate populations of neurons having receptive sites for both transmitters and innervating certain common target neurons.

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
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2794119

Citation

Pickel, V M., et al. "Cellular Substrates for Interactions Between Neurons Containing Phenylethanolamine N-methyltransferase and GABA in the Nuclei of the Solitary Tracts." The Journal of Comparative Neurology, vol. 286, no. 2, 1989, pp. 243-59.
Pickel VM, Chan J, Milner TA. Cellular substrates for interactions between neurons containing phenylethanolamine N-methyltransferase and GABA in the nuclei of the solitary tracts. J Comp Neurol. 1989;286(2):243-59.
Pickel, V. M., Chan, J., & Milner, T. A. (1989). Cellular substrates for interactions between neurons containing phenylethanolamine N-methyltransferase and GABA in the nuclei of the solitary tracts. The Journal of Comparative Neurology, 286(2), 243-59.
Pickel VM, Chan J, Milner TA. Cellular Substrates for Interactions Between Neurons Containing Phenylethanolamine N-methyltransferase and GABA in the Nuclei of the Solitary Tracts. J Comp Neurol. 1989 Aug 8;286(2):243-59. PubMed PMID: 2794119.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cellular substrates for interactions between neurons containing phenylethanolamine N-methyltransferase and GABA in the nuclei of the solitary tracts. AU - Pickel,V M, AU - Chan,J, AU - Milner,T A, PY - 1989/8/8/pubmed PY - 1989/8/8/medline PY - 1989/8/8/entrez SP - 243 EP - 59 JF - The Journal of comparative neurology JO - J. Comp. Neurol. VL - 286 IS - 2 N2 - Adrenaline and gamma-aminobutyric acid (GABA) have been implicated in autonomic functions involving the intermediate and caudal portions of the medial nuclei of the solitary tracts (m-NTS). We sought to determine whether there was a cellular basis for direct intracellular or synaptic interactions between these transmitters in neurons in the m-NTS of rat brain by using dual-labeling immunocytochemical methods. Light microscopy revealed immunoautoradiographic labeling for the adrenaline-synthesizing enzyme phenylethanolamine N-methyltransferase (PNMT) in perikarya and processes in close proximity to cells demonstrating peroxidase reaction product for GABA. Electron microscopy of the intermediate m-NTS at the level of the area postrema further established the localization of immunoautoradiographic and peroxidase labels for PNMT and GABA in common as well as separate perikarya and dendrites. All axon terminals were labeled separately for PNMT and GABA. The PNMT-labeled terminals formed both symmetric and asymmetric synapses, whereas the GABA-labeled terminals formed exclusively symmetric synapses. Twenty-four percent (n = 42) of the PNMT- and 39% (n = 128) of the GABA-labeled terminals formed synaptic junctions on unlabeled soma and dendrites. Occasionally both types of terminals converged on a common unlabeled dendrite and on GABA-labeled dendrites. Only 3% of the PNMT- and 12% of the GABA-containing terminals formed synapses on PNMT-labeled soma and dendrites, whereas 7% of each type formed synapses with GABA-labeled profiles. The remaining labeled terminals lacked synaptic relations within the sections examined. The autoradiographic results were confirmed and extended by means of immunogold labeling for PNMT in combination with peroxidase-antiperoxidase localization of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD). GAD-labeled terminals formed symmetric synapses with dendrites that were either unlabeled or contained low levels of PNMT (gold particles) or PNMT and GAD. We conclude that in caudal, more cardiovascular portions of the NTS, adrenaline and GABA may coexist, but they are more commonly detected in separate populations of neurons having receptive sites for both transmitters and innervating certain common target neurons. SN - 0021-9967 UR - https://www.unboundmedicine.com/medline/citation/2794119/Cellular_substrates_for_interactions_between_neurons_containing_phenylethanolamine_N_methyltransferase_and_GABA_in_the_nuclei_of_the_solitary_tracts_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0021-9967&date=1989&volume=286&issue=2&spage=243 DB - PRIME DP - Unbound Medicine ER -