Faculty Collaboration Database

GABAergic and glycinergic synapses onto neurokinin-1 receptor-immunoreactive neurons in the pre-Bötzinger complex of rats: light and electron microscopic studies. Eur J Neurosci 2002 Sep;16(6):1058-66

Date

10/18/2002

Pubmed ID

12383234

DOI

10.1046/j.1460-9568.2002.02163.x

Scopus ID

2-s2.0-18744393363 (requires institutional sign-in at Scopus site)   24 Citations

Abstract

The pre-Bötzinger complex (preBötC) in the ventrolateral medulla is thought to be the kernel for respiratory rhythm generation. Neurons in the preBötC contain intense neurokinin-1 receptor (NK1R) immunoreactivity. Some of these neurons in the adult preBötC are presumed to be the pre-inspiratory interneurons that are essential for generating respiratory rhythm in the neonate. Chloride-mediated synaptic inhibition is critical for rhythmogenesis in the adult. The present study used immunofluorescence histochemistry and immunogold-silver staining to determine the inhibitory synaptic relationship between glutamic acid decarboxylase (GAD)- or glycine transporter 2 (GlyT2)-immunoreactive (ir) boutons and NK1R-ir neurons in the preBötC of adult rats. Under the confocal microscope, we found that GAD- and GlyT2-ir boutons were in close apposition to NK1R-ir somas and dendrites in the preBötC. Under the electron microscope, GAD- and GlyT2-ir terminals were in close apposition to NK1R-ir somas and dendrites. Symmetric synapses were identified between GAD- or GlyT2-ir terminals and NK1R-ir neurons. A total of 51.6% GAD-ir and 38.2% GlyT2-ir terminals were found to contact or make synapses with NK1R-ir profiles, respectively. GAD- and GlyT2-ir terminals synapsed not only upon NK1R-ir neurons but also upon NK1R immuno-negative neurons. NK1R-ir neurons received both symmetric (presumed inhibitory) and asymmetric (presumed excitatory) synapses. Thus, the present findings provide the morphological basis for inhibitory inputs to NK1R-ir neurons in the preBötC, consistent with the suggestion that chloride-mediated synaptic inhibition may contribute importantly to rhythm generation by controlling the membrane potential trajectory and resetting rhythmic bursting of the kernel neurons in the adult.

Author List

Liu YY, Wong-Riley MT, Liu JP, Jia Y, Liu HL, Jiao XY, Ju G

MESH terms used to index this publication - Major topics in bold

Amino Acid Transport Systems, Neutral
Animals
Cell Size
Chloride Channels
Dendrites
Glutamate Decarboxylase
Glycine
Glycine Plasma Membrane Transport Proteins
Immunohistochemistry
Medulla Oblongata
Microscopy, Electron
Neural Inhibition
Presynaptic Terminals
Rats
Rats, Sprague-Dawley
Receptors, Neurokinin-1
Respiratory Center
Respiratory Physiological Phenomena
Synaptic Membranes
Synaptic Transmission
gamma-Aminobutyric Acid