Abstract
Abstract: :
Purpose: We have reported that there is a good correlation between body temperature and the amplitudes of the a– and b–waves of the ERG (IOVS 2002). The purpose of this study was to determine if the amplitudes and implicit times of the oscillatory potentials (OPs) are also correlated with the body temperature. Methods: Six–week–old, female BALB/c mice were used. After overnight dark–adaptation, the mice were anesthetized with an intramuscular injection of a mixture of ketamine, xylazine, and urethane, and a cotton–wick electrode was placed on the cornea as the active electrode. The reference electrode was placed subcutaneously over the nasal bone. The light for the stimulus was obtained from 100–W quartz–halogen light bulb. The stimulus intensity was 3000 lux on the surface of the cornea. The duration of the stimulus was controlled by an electromagnetic shutter at 5 ms. The responses were amplified and preamplifier bandwidth was set at 15–1000 Hz. Body temperature was changed to 27°, 30°, 33°, and 36ºC by changing the ambient temperature. The peak latency and the amplitude of OP1, OP2, OP3, and OP4 were measured. Results: With a decrease of body temperature, the amplitudes of the OPs were reduced. The reduction was the largest for OP2, and at 27º C, no clear OPs were recorded. The peak latencies of all of the OPs were prolonged with a decrease of body temperature especially at 30ºC. The pattern of alterations of the implicit times of each wave with a decrease of body temperature was systematic. Conclusions: A change of body temperature affects both the amplitude and peak latency of the OPs. Compared with our previous study, OPs were more severely affected than the amplitudes and implicit times of the a– or b–waves of the ERG.
Keywords: electroretinography: non–clinical • retina • electrophysiology: non–clinical