Types and spatial distribution of vasoactive intestinal polypeptide (VIP)-containing synapses in the rat visual cortex.
In the rat visual cortex vasoactive intestinal polypeptide (VIP)-containing structures were studied by means of light and electron microscopy and image analysis. VIP-immunoreactive axon terminals were found to form symmetric synapses with small dendritic shafts, dendritic spines and somata of pyramidal cells and interneurons. VIP-terminals often occurred in pairs with VIP-negative, asymmetric synapses on the same postsynaptic structure. VIP-immunostained dendrites and perikarya were contacted by a purely asymmetric and a mixed population of VIP-negative terminals, respectively. Synaptic connections between two VIP-neurons are seldom as compared to the other types of VIP-synapses. Quantitative studies obtained by the image analysis of VIP-stained boutons and dendritic particles in light microscopic preparations suggest a distinct laminar distribution. Dendritic particles are most frequent in layers I-II, whereas axonal boutons have three laminar accumulations: at the border of layers I-II, in layer IV and layer VI. Together with previous results, the present findings argue for a non-random spatial distribution of VIP-boutons.
First Departement of Anatomy, Semmelweis University Medical School, Budapest, Hungary.
F
F
Hajós
K
K
Zilles
A
A
Schleicher
M
M
Kálmán
D000818:Animals; D001369:Axons / Q000032:analysis / Q000648:ultrastructure; D003712:Dendrites / Q000032:analysis / Q000648:ultrastructure; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D013569:Synapses / Q000032:analysis* / Q000648:ultrastructure; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*; D014793:Visual Cortex / Q000032:analysis / Q000166:cytology*
D014660:Vasoactive Intestinal Peptide