Insular cortical and amygdaloid fibers are in contact with posterolateral hypothalamic neurons projecting to the nucleus of the solitary tract in the rat.
After ipsilateral injections of cholera toxin B subunit (CTb) into the nucleus of the solitary tract (NST) and biotinylated dextran amine (BDA) into the insular cortex (IC) or into the central amygdaloid nucleus (ACe) in the rat, the prominent overlapping distribution of CTb-labeled neurons and BDA-labeled axon terminals was found in the posterolateral hypothalamus (PLH) region just medial to the subthalamic nucleus ipsilateral to the injection sites. At the electron microscopic level, the IC terminals formed asymmetrical synaptic contacts with dendrites and dendritic spines of the NST-projecting PLH neurons, whereas the ACe terminals formed symmetrical synaptic contacts with somata and dendrites of the NST-projecting PLH neurons. The present data suggest that output signals from the IC and ACe may exert excitatory and inhibitory influences, respectively, upon the PLH neurons that project to the NST for regulating cardiovascular functions.
Tsumori
Toshiko
T
Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo 693-8501, Japan.
Yokota
Shigefumi
S
Kishi
Toshiro
T
Qin
Yi
Y
Oka
Tatsuro
T
Yasui
Yukihiko
Y
D000679:Amygdala / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives; D002540:Cerebral Cortex / Q000502:physiology* / Q000648:ultrastructure; D002772:Cholera Toxin; D003911:Dextrans; D005456:Fluorescent Dyes; D007026:Hypothalamic Area, Lateral / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D017552:Solitary Nucleus / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*
D003911:Dextrans; D005456:Fluorescent Dyes; C076397:biotinylated dextran amine; D001710:Biotin; D002772:Cholera Toxin