GABAergic neurons in the ventrolateral subnucleus of the nucleus tractus solitarius are in contact with Kölliker-Fuse nucleus neurons projecting to the rostral ventral respiratory group and phrenic nucleus in the rat.
After ipsilateral injections of biotinylated dextran amine (BDA) into the ventrolateral subnucleus of the nucleus tractus solitarius (vlNTS) and Fluoro-gold (FG) into the rostral ventral respiratory group (rVRG) region or into the phrenic nucleus (PhN) region in the rat, an overlapping distribution of BDA-labeled axon terminals and FG-labeled neurons was found in the Kölliker-Fuse (KF) nucleus ipsilateral to the injection sites. Using retrograde tracing combined with immunohistochemistry for glutamic acid decarboxylase isoform 67 (GAD67), we indicated that as many as 40% of the vlNTS neurons projecting to the KF were immunoreactive for GAD67. Using a combination of anterograde and retrograde tracing techniques, and immunohistochemistry for GAD67, we further demonstrated that the vlNTS axon terminals with GAD67 immunoreactivity established close contact to the rVRG- or PhN-projecting KF neurons. The present results suggest that GABAergic vlNTS fibers may exert inhibitory influences on the rVRG- as well as PhN-projecting KF neurons and these circuits may be involved in the respiratory reflexes such as the Hering-Breuer reflex.
Yokota
Shigefumi
S
Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo 693-8501, Japan.
Tsumori
Toshiko
T
Oka
Tatsuro
T
Nakamura
Sawako
S
Yasui
Yukihiko
Y
D000818:Animals; D001370:Axonal Transport / Q000502:physiology; D001710:Biotin / Q000031:analogs & derivatives / Q000737:chemistry; D002352:Carrier Proteins / Q000378:metabolism; D003911:Dextrans / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology; D017729:Presynaptic Terminals / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012125:Respiratory Center / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D017552:Solitary Nucleus / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D013266:Stilbamidines / Q000737:chemistry; D009435:Synaptic Transmission / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D002352:Carrier Proteins; D003911:Dextrans; D005456:Fluorescent Dyes; D013266:Stilbamidines; C076397:biotinylated dextran amine; D005680:gamma-Aminobutyric Acid; D001710:Biotin; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1