Distribution and colocalization of neurotransmitters and receptors in the pre-Bötzinger complex of rats.
The pre-Bötzinger complex (PBC), thought to be the center of respiratory rhythm generation, is a cell column ventrolateral to the nucleus ambiguus. The present study analyzed its cellular and neurochemical composition in adult rats. PBC neurons were mainly oval, fusiform, or multipolar in shape and small to medium in size. Neurokinin-1 receptor, a marker of the PBC, was present in the plasma membrane of mostly medium and small neurons and their associated processes and boutons. Among neurons immunoreactive for different neurotransmitter or receptor candidates, various numbers were colocalized with neurokinin-1 receptor. The highest ratio was with nitric oxide synthase (52.72%), and the lowest was with glycine receptors (31.93%). Glutamic acid decarboxylase- and glycine transporter 2-immunoreactive boutons, as well as GABA(A) receptor-immunoreactive plasma membrane processes and boutons, were also identified in the PBC. PBC neurons exhibited different levels of cytochrome oxidase activity, indicating their various energy demands. Our results suggest that synaptic interactions within the PBC of adult rats involve a variety of neurotransmitter and receptor types and that nitric oxide may play an important role in addition to glutamate, GABA, glycine, and neurokinin.
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Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Wong-Riley
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D026921:Amino Acid Transport Systems, Neutral / Q000032:analysis; D000818:Animals; D003576:Electron Transport Complex IV / Q000032:analysis; D005968:Glutamate Decarboxylase / Q000032:analysis; D018698:Glutamic Acid / Q000032:analysis*; D050487:Glycine Plasma Membrane Transport Proteins; D007124:Immunoenzyme Techniques; D008526:Medulla Oblongata / Q000737:chemistry* / Q000166:cytology / Q000201:enzymology; D009474:Neurons / Q000737:chemistry / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000032:analysis; D011963:Receptors, GABA-A / Q000032:analysis*; D018080:Receptors, GABA-B / Q000032:analysis; D018009:Receptors, Glycine / Q000032:analysis; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis; D018040:Receptors, Neurokinin-1 / Q000032:analysis*; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D026921:Amino Acid Transport Systems, Neutral; D003576:Electron Transport Complex IV; D005968:Glutamate Decarboxylase; D018698:Glutamic Acid; D050487:Glycine Plasma Membrane Transport Proteins; D019001:Nitric Oxide Synthase; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate; D018040:Receptors, Neurokinin-1; D005680:gamma-Aminobutyric Acid; C493269:Slc6a5 protein, rat; C104723:glutamate receptor ionotropic, AMPA 3; C104722:glutamate receptor ionotropic, AMPA 2