Ultrastructural changes of the olfactory bulb in manganese-treated mice.

The effect of manganese toxicity on the ultrastructure of the olfactory bulb was evaluated. Male albino mice were injected intraperitoneally with MnCl2 (5 mg/Kg/day) five days per week during nine weeks. The control group received NaCl (0.

In mice the efficiency of immunization with Venezuelan Equine Encephalomyelitis virus TC-83 is transiently increased by dehydroepiandrosterone.

To determine whether treatment with dehydroepiandrosterone (DHEA) improves the efficiency of immunization against the Venezuelan Equine Encephalomyelitis (VEE) virus, mice were vaccinated with the TC-83 VEE virus. DHEA (10 mg/kg) was administered in a single dose, 4 hours before vaccination. IgM antibody titers were determined at days 7, 14 and 21 post-immunization.

High intensity light increases olfactory bulb melatonin in Venezuelan equine encephalitis virus infection.

In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack.

Exposure to 2500 lux increases serum melatonin in Venezuelan equine encephalomyelitis.

When mice infected with the Venezuelan equine encephalomyelitis (VEE) virus were exposed to 2500 lux with a 12 h light: 12 h dark photoperiod, the serum levels of melatonin (MLT) remained constantly elevated. In mice exposed to 400 lux low levels of serum MLT were detected during the day and high levels during the night. An increase in the survival rate of the infected mice from 6 to 13 days after virus inoculation was also observed.

Decrease in spontaneous motor activity and in brain lipid peroxidation in manganese and melatonin treated mice.

In the present study, we have evaluated whether melatonin (MEL) modulates Mn-induced decrease in spontaneous motor activity (SMA) and lipid peroxidation, estimated as malondialdehyde (MDA) formation, in several brain regions. In mice treated with manganese a decrease in SMA after 2 weeks of treatment was observed. In the group treated with Mn+MEL a significant greater reduction in SMA was detected at 4 weeks.