Neurological and behavioral effects of intracranial administration of mercuric chloride on rats

Abstract

Mercuric chloride was injected intracranially into the rat brain in the region of the fourth ventricle via the foramen magnum. Responses to a single treatment of 0.3 mg/kg HgCl2, 0.03 mg/kg HgCl2, or carrier solution were followed for 10 days. Changes in the rats' behavior and motor coordination were observed 24-48 hr after treatment with HgCl2. Underwater swimming and decreased grooming and feeding were characteristic of mercury-treated rats. Decreased balancing ability and crossing of hind limbs suggested altered motor coordination. Rats treated with mercury often exhibited decreased body temperature, matting of fur about the eyes and perineal region, apparent visual impairment, decreased body weight, and diarrhea.

Selenomethionine reduces visual deficits due to developmental methylmercury exposures

“…However, we cannot exclude the possibility that other structures within the zebrafish visual system are also altered by MeHg exposure, as has been shown in other preparations [30,57,58]. In fact, it is highly likely that these other regions are also sensitive and that it is the combined effect of MeHg exposure on various neural circuits that leads to the changes in visual behaviors observed.…”

“…Clearly, central nervous system integration with the optic tectum and/or cerebellum, altered function of the optic nerve, and/or sensorimotor deficiencies are all additional mechanisms that also could be involved. Lesions in brain regions important to visual discrimination, e.g., occipital lobe and striate cortex, after postnatal exposures to MeHg have been noted and have led to restricted peripheral vision [57,58]. In fishes, the optic tectum is the parallel brain region and it would not be unexpected to find structural and/or functional alterations there, as well.…”

Inorganic Mercury Poisoning, Rat

“…However, it is not yet known whether inorganic mercury causes damage to neurons or glia in these regions. In an attempt to bypass the protective effects of the blood-brain barrier and to examine the direct effects of inorganic mercury, several investigators Inorganic Mercury Poisoning, Rat 99 (Venable and Mills 1977;Gallagher et al 1982) injected or iontophoresed mercuric chloride directly into the cerebrum. Lesions induced by intracranial mercuric chloride were similar to those induced by methylmercury administered in the same fashion.…”