Effects of different anesthetics on oscillations in the rat olfactory bulb.

摘要

Different types of oscillations in the olfactory bulb (OB), including theta (1 to 4 and 5 to 12 Hz), beta (13 to 30 Hz), and gamma oscillations (31 to 64 and 65 to 90 Hz), are important in olfactory information processing and olfactory-related functions and have been investigated extensively in recent decades. The awake and anesthetized states, 2 different brain conditions, are used widely in electrophysiologic studies of OB. Chloral hydrate, pentobarbital, and urethane are commonly used anesthetics in these studies. However, the influence of these anesthetics on the oscillations has not been reported. In the present study, we recorded the local field potential (LFP) in the OB of rats that were freely moving or anesthetized with these agents. Chloral hydrate and pentobarbital had similar effects: they slightly affected the power of theta oscillations; significantly increased the power of beta oscillations; significantly decreased the power of gamma oscillations, and showed similar recovery of gamma oscillations. Urethane had very different effects: it significantly increased oscillations at 1 to 4 Hz but decreased those at 5 to 12 Hz, decreased beta and gamma oscillations, and showed no overt recovery in gamma oscillations. These results provide experimental evidence of different effects of various anesthetics on OB oscillations and suggest that the choice of anesthetic should consider the experimental application.