Ultrastructural analysis of low-threshold mechanoreceptive vibrissa afferent boutons in the cat trigeminal caudal nucleus.
10.5115/acb.2010.43.4.340
- Author:
Sang Kyoo PAIK
1
;
Seung Ki CHOI
;
Jong Wook LEE
;
Tae Heon KIM
;
Dong Kuk AHN
;
Atsushi YOSHIDA
;
Yun Sook KIM
;
Yong Chul BAE
Author Information
1. Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea. ycbae@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Trigeminal;
Low-threshold mechanoreception;
Ultrastructure;
Synapse;
Vibrissa afferent
- MeSH:
Animals;
Cats;
Dendrites;
Mitochondrial Size;
Synapses;
Trigeminal Caudal Nucleus
- From:Anatomy & Cell Biology
2010;43(4):340-346
- CountryRepublic of Korea
- Language:English
-
Abstract:
Ultrastructural parameters related to synaptic release and their correlation with synaptic connectivity were analyzed in the low-threshold mechanoreceptive vibrissa afferent boutons in laminae III and IV of the trigeminal caudal nucleus (Vc). Rapidly adapting vibrissa afferents were intra-axonally labeled, and quantitative ultrastructural analyses with serial sections were performed on the labeled boutons and their presynaptic endings (p-endings). The volume of the labeled boutons was widely distributed from small to large ones (0.8~12.3 microm3), whereas the p-endings were small and uniform in size. The volume of the labeled boutons was positively correlated with the ultrastructural parameters such as mitochondrial volume (correlation coefficient, r=0.96), active zone area (r=0.82) and apposed surface area (r=0.79). Vesicle density (r=-0.18) showed little correlation to the volume of labeled boutons, suggesting that the total vesicle number of a bouton is proportional to its volume. In addition, the bouton volume was positively correlated with the number of p-endings (r=0.52) and with the number of dendrites postsynaptic to the labeled bouton (r=0.83). These findings suggest that low-threshold mechanoreception conveyed through vibrissa afferents is processed in a bouton size-dependent manner in the Vc, which may contribute to the sensory-motor function of laminae III/IV in Vc.
