1. Sensory Neurons in the Human Geniculate Ganglion
- Author
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Noriyuki Kanda, Takehiro Yajima, Yu Yamaguma, Hiroyuki Ichikawa, Tadasu Sato, Souichi Kokubun, Yu Sasaki, and Nobuyuki Sasahara
- Subjects
Male ,0301 basic medicine ,Histology ,Sensory Receptor Cells ,TRPV1 ,Scarpa's ganglion ,Sensory system ,Biology ,Somatosensory system ,03 medical and health sciences ,0302 clinical medicine ,Cadaver ,medicine ,Humans ,Aged ,Aged, 80 and over ,Nodose Ganglion ,Anatomy ,Middle Aged ,Geniculate Ganglion ,Immunohistochemistry ,Ganglion ,030104 developmental biology ,Nociception ,medicine.anatomical_structure ,Female ,Geniculate ganglion ,030217 neurology & neurosurgery - Abstract
The geniculate ganglion (GG) contains visceral and somatic sensory neurons of the facial nerve. In this study, the number and cell size of sensory neurons in the human GG were investigated. The estimated number of GG neurons ranged from 1,580 to 2,561 (mean ± SD = 1,960 ± 364.6). The cell size of GG neurons ranged from 393.0 to 2,485.4 μm2 (mean ± SD = 1,067.4 ± 99.5 μm2). Sensory neurons in the GG were significantly smaller in size than those in the dorsal root (range = 326.6-5343.4 μm2, mean ± SD = 1,683.2 ± 203.8 μm2) or trigeminal ganglia (range = 349.6-4,889.28 μm2, mean ± SD = 1,529.0 ± 198.48 μm2). Sensory neurons had similar cell body sizes in the GG and nodose ganglion (range = 357.2-3,488.33 μm2, mean ± SD = 1,160.4 ± 156.61 μm2). These findings suggest that viscerosensory neurons have smaller cell bodies than somatosensory neurons. In addition, immunohistochemistry for several neurochemical substances was performed on the human GG. In the ganglion, sensory neurons were mostly immunoreactive for secreted protein, acidic and rich in cysteine-like 1 (94.3%). One third of GG neurons showed vesicular glutamate transporter 2 immunoreactivity (31.3%). Only 7.3% of GG neurons were immunoreactive for transient receptor potential cation channel subfamily V member 1. Sensory neurons in the human GG may respond to gustatory, nociceptive, and/or mechanoreceptive stimuli from tongues, soft palates, and external auditory canals.
- Published
- 2017