Glutamatergic neurons in the Kölliker-Fuse nucleus project to the rostral ventral respiratory group and phrenic nucleus: a combined retrograde tracing and in situ hybridization study in the rat.
Kölliker-Fuse nucleus (KF) neurons are considered to excite motoneurons in the phrenic nucleus (PhN) during inspiration through its projection to the PhN and/or to the rostral ventral respiratory group (rVRG), which in turn projects to the PhN, probably by releasing glutamate from their axon terminals. Using a combined retrograde tracing and in situ hybridization technique, here we demonstrate that most of the KF neurons projecting to the PhN and rVRG contain vesicular glutamate transporter 2 (VGLUT2) mRNA but not glutamic acid decarboxylase 67 (GAD67) mRNA, providing definitive evidence that these neurons are glutamatergic. Together with previous data by Stornetta et al. [Stornetta, R.L., Sevigny, C.P., Guyenet, P.G., 2003b. Inspiratory argumenting bulbospinal neurons express both glutamatergic and enkephalinergic phenotypes. J. Comp. Neurol. 455, 113-124], indicating that PhN-projecting rVRG neurons are VGLUT2 mRNA-positive, the present results suggest that the glutamatergic KF-PhN pathway and/or the glutamatergic KF-rVRG-PhN pathway transmit excitatory outputs of KF neurons to the PhN neurons during inspiration.
Yokota
Shigefumi
S
Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo 693-8501, Japan.
Oka
Tatsuro
T
Tsumori
Toshiko
T
Nakamura
Sawako
S
Yasui
Yukihiko
Y
D000818:Animals; D001370:Axonal Transport; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000378:metabolism*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D010791:Phrenic Nerve / Q000033:anatomy & histology / Q000378:metabolism*; D011149:Pons / Q000033:anatomy & histology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration; D012125:Respiratory Center / Q000033:anatomy & histology / Q000378:metabolism*; D013194:Staining and Labeling; D009435:Synaptic Transmission / Q000502:physiology; D050599:Vesicular Glutamate Transport Protein 2 / Q000235:genetics; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D012333:RNA, Messenger; C493475:Slc17a6 protein, rat; D050599:Vesicular Glutamate Transport Protein 2; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1