The synaptic interrelationships between primary afferent terminals, cuneothalamic relay neurons and GABA-immunoreactive boutons in the rat cuneate nucleus.
The present study described an ultrastructural synaptic configurations between primary afferent terminals (PATs), cuneothalamic relay neurons (CTNs) and GABA-immunoreactive (GABA-IR) boutons in the cuneate nucleus of rats using cervicothoracic dorsal rhizotomies, retrograde transport of wheat germ agglutinin conjugated with horseradish peroxidase complex (WGA-HRP) and anti-GABA immunogold labelling methods. With this procedure, direct synaptic relationships between the PATs, CTNs and GABA-IR boutons have been demonstrated. The most remarkable feature was the observation whereby an immunogold-labelled GABA-IR bouton was presynaptic to a WGA-HRP labelled dendrite of CTN and a degenerating PAT; the same PAT was in turn presynaptic to the HRP-labelled dendrite. This was evident in ten out of a total of 133 synaptic configurations that were closely scrutinized. Results of this study support the concept that GABA-IR boutons are not only involved in presynaptic inhibition on the primary afferent input to the cuneothalamic relay neurons, but also exert a simultaneous postsynaptic inhibition on these cells.
Lue
J H
JH
Department of Anatomy, College of Medicine, National Taiwan University, Taipei, Taiwan.
Jiang-Shieh
Y F
YF
Shieh
J Y
JY
Wen
C Y
CY
D000818:Animals; D000918:Antibody Specificity; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000737:chemistry / Q000166:cytology*; D016253:Microscopy, Immunoelectron; D009475:Neurons, Afferent / Q000737:chemistry / Q000648:ultrastructure*; D017729:Presynaptic Terminals / Q000737:chemistry / Q000648:ultrastructure*; D051381:Rats; D017208:Rats, Wistar; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000276:immunology
D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D005680:gamma-Aminobutyric Acid