Comparative study on the distribution of Pacinian corpuscles in the pancreas

Shuang-Qin Yi^1*Ting Yang²Ke Ren³Xiangquan Xiangquan Chen³Taku Toriumi⁴Rujia Li⁵Jun Li⁶Kounosuke Tokita⁷

• ¹Department of Frontier Health Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Hachioji, Japan
• ²Tokyo Metropolitan University, Hachioji, Japan
• ³Qujing Normal University, Qujing, Yunnan, China
• ⁴School of Life Dentistry, Nippon Dental University, Tokyo, Japan
• ⁵Department of Hepatobiliary Surgery, Third People's Hospital of Gansu Province, Lanzhou, Gansu, China
• ⁶State Key Laboratory of Oncogenes and Related Genes, School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai, China
• ⁷School of Physical Therapy, Faculty of Health and Medical Care, Saitama Medical University, Saitama City, Japan

Pacinian corpuscles (PCs) are pressure-and vibration-sensitive mechanoreceptors found in hairless skin, external genitalia, joints, ligaments, lymph nodes, prostate, bladder, etc.TheyWhile they are also commonly founddocumented in the pancreas of cats, and although a few studies have reported their presence in the human pancreas, the actual presence of PCs in the normal pancreas remains speculative. The present study therefore investigated the distribution of PCs in the normal human pancreas and compared the findings with those in several other animal species. The study subjects included Pancreatic tissues from 74 human cadaver specimens, 3 Cynictis penicillata, 2 Saguinus mystaxs, 1 Felis domesticus, and 10 Suncus murinus. Pancreatic tissues were prepared as paraffin sections for histological and immunohistochemical analyses of the main constituents of PCs (central axon, inner core, and outer core capsule). PCs were found in the pancreas of five human cadavers, (7%), as well as in one C. penicillata, one S. mystax and one F. domesticus but not in S. murinus. The PCs varied in size, ranging from 0.2 to 0.7 mm. PCs inwith the largest in the human pancreas measuring up to 1,106 μmfar exceeding those in animal pancreata of C. penicillata, S. mystax, and F. domesticus were more, but less numerous and denser than those in the human pancreas, and theyanimals. Morphologically, animal PCs were mainly typical oval shapes, whereas PCs in the human pancreas were mostly irregular in shape. In addition, we found that PCs in animals and human pancreata had similar structures, with consistent expression of protein gene product 9.5, in axonic profiles, and diffuse vimentin immunoreactivity in the inner core, outer core, and capsule. This study confirmed the presence of PCs in a small number of healthy humans and some animal pancreata. The number, distribution 4 characteristics, and morphology of PCs in the pancreata of animals and humans are quite different; however, their structures and immunohistochemical profiles are similar. The presence of PCs in the normal human pancreas is also a mystery, and the physiological role of PCs in the human pancreas requires further clarification.