Quantitative Ultrastructural Analysis of Endings Presynaptic to the Tooth Pulp Afferent Terminals in the Trigeminal Oral Nucleus
International Journal of Oral Biology
; : 133-139, 2016.
Article
en Ko
| WPRIM
| ID: wpr-124489
Biblioteca responsable:
WPRO
ABSTRACT
The ultrastructural parameters related to synaptic release of endings which are presynaptic to tooth pulp afferent terminals (p-endings) were analyzed to understand the underlying mechanism for presynaptic modulation of tooth pulp afferents. Tooth pulp afferents were labelled by applying wheat-germ agglutinin conjugated horseradish peroxidase to the rat right lower incisor, whereafter electron microscopic morphometric analysis with serial section and reconstruction of p-endings in the trigeminal oral nucleus was performed. The results obtained from 15 p-endings presynaptic to 11 labeled tooth pulp afferent terminals were as follows. P-endings contained pleomorphic vesicles and made symmetrical synaptic contacts with labeled terminals. The p-endings showed small synaptic release-related ultrastructural parameters: volume, 0.82 ± 0.45 µm³ (mean ± SD); surface area, 4.50 ± 1.76 µm²; mitochondrial volume, 0.15 ± 0.07 µm³; total apposed surface area, 0.69 ± 0.24 µm²; active zone area, 0.10 ± 0.04 µm²; total vesicle number, 1045 ± 668.86; and vesicle density, 1677 ± 684/µm². The volume of the p-endings showed strong positive correlation with the following parameters: surface area (r=0.97, P<0.01), mitochondrial volume (r=0.56, P<0.05), and total vesicle number (r=0.73, P<0.05). However, the volume of p-endings did not positively correlate or was very weakly correlated with the apposed surface area (r=-0.12, P=0.675) and active zone area (r=0.46, P=0.084). These results show that some synaptic release-related ultrastructural parameters of p-endings on the tooth pulp afferent terminals follow the "size principle" of Pierce and Mendell (1993) in the trigeminal nucleus oralis, but other parameters do not. Our findings may demonstrate a characteristic feature of synaptic release associated with p-endings.
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Texto completo:
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Índice:
WPRIM
Asunto principal:
Diente
/
Núcleos del Trigémino
/
Tamaño Mitocondrial
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Peroxidasa de Rábano Silvestre
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Incisivo
Límite:
Animals
Idioma:
Ko
Revista:
International Journal of Oral Biology
Año:
2016
Tipo del documento:
Article