Hypoalgesia and recovery in methylmercury-exposed rats

Methylmercury (MeHg), the causal substrate in Minamata disease, can lead to severe and chronic neurological disorders. The main symptom of Minamata disease is sensory impairment in the four extremities; however, the sensitivity of individual sensory modalities to MeHg has not been investigated exten...

Full description

Saved in:
Bibliographic Details
Published in:Journal of toxicological sciences 2021, Vol.46(6), pp.303-309
Main Authors: Shinoda, Yo, Yamada, Yuta, Yoshida, Eiko, Takahashi, Tsutomu, Tsuneoka, Yayoi, Eto, Komyo, Kaji, Toshiyuki, Fujiwara, Yasuyuki
Format: Article
Language:English
Subjects:
Animals
Dimethylmercury
Exposure
Extremities
Hypesthesia - etiology
Hypesthesia - physiopathology
Hypoalgesia
Male
Mercury (metal)
Mercury Poisoning, Nervous System - etiology
Mercury Poisoning, Nervous System - physiopathology
Methylmercury
Methylmercury Compounds - administration & dosage
Methylmercury Compounds - toxicity
Minamata disease
Neurological diseases
Oral administration
Pain
Pain - physiopathology
Pain perception
Pain sensitivity
Rats
Rats, Wistar
Rodents
Sensory modality
Substrates
Toxicity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Methylmercury (MeHg), the causal substrate in Minamata disease, can lead to severe and chronic neurological disorders. The main symptom of Minamata disease is sensory impairment in the four extremities; however, the sensitivity of individual sensory modalities to MeHg has not been investigated extensively. In the present study, we performed stimulus-response behavioral experiments in MeHg-exposed rats to compare the sensitivities to pain, heat, cold, and mechanical sensations. MeHg (6.7 mg/kg/day) was orally administered to 9-week-old Wistar rats for 5 days and discontinued for 2 days, then administered daily for another 5 days. The four behavioral experiments were performed daily on each rat from the beginning of MeHg treatment for 68 days. The pain sensation decreased significantly from day 11 onwards, but recovered to control levels on day 48. Other sensory modalities were not affected by MeHg exposure. These findings suggest that the pain sensation is the sensory modality most susceptive to MeHg toxicity and that this sensitivity is reversible following discontinuation of the exposure.
ISSN:0388-1350
1880-3989
DOI:10.2131/jts.46.303