삼차신경 운동핵에서 교근 근방추 구심성 신경섬유 종말지의 미세구조
Morphology of the terminal arbors from the masseteric muscle spindle afferents in the trigeminal motor nucleus
최수한, 김덕윤, 구본천,
소속 상세정보
최수한 ( ) - 경희대학교 식품공학과
김덕윤 ( ) - 경희대학교 식품공학과
구본천 ( ) - 경희대학교 식품공학과
KMID : 0360119940160030321
Abstract
Muscle spindle afferents from masseter muscle were labelled by the intra-axonal HRP injection and were processed for light microscopic reconstruction.
Regions containing terminal arbors scattered in the central portion of the masseteric motor neuron pool(type I a) and those restricted to 2-3 small portion of it(type II) were selected and processed for electronmicroscopic analysis with serial
sections.
The shape of the labelled boutons was dome or elongated shape. Scalloped or glomerulus shape with peripherial indentation containing pre or postsynaptic neuronal propiles, which is occasionally found in the trigeminal main sensory nucleus and
spinal
dorsal horn, was not observed.
Both type Ia and type II boutons had pale axoplasm and contained clear, spherical vesicles of uniform size(dia : 49-52nm) and occasionally large dense cored vesicles(dia : 87-118nm). The synaptic vesicles were evenly distributed throughout the
boutons
although there was a slight tendency of vesicles to accumulate at the presynaptic site.
The average of short and long diameter(short D+long D/2) of type I a bouton was smaller than that of type II bouton. All the labelled boutons, which showed prominent postsynaptic density, mare synaptic area and multiple synaptic contact, made
asymmetrical synaptic contact with postsynaptic neuronal propiles.
Most of the type Ia and type II boutons mate synaptic contact with only one neuronal propile and boutons which shows synaptic contact or more neuronal propiles was not observed.
Most of the type Ia boutons(87.2%) were presynaptic to the soma or proximal dendrite and a few remainder(12.8%) made synaptic contact with dendritic shaft or distal dendrite.
In contrast, majority of type II boutons showed synaptic contact with dendritic shaft and remainder with soma or proximal dendrite.
In conclusion, terminal boutons which participate in the excitatory monosynaptic jaw jerk reflex made synaptic contact with more proximal region of the neuron, and showed very simple synaptic connection, compared with those from the primary
afferenst in
the other region of the central nervous system such as spinal dorsal horn and trigeminal main sensory nucleus which assumed to be responsible for the mediating pain, tactile sensation, sensory processing or sensory discrimination.
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