The action of agonists and an antagonist of GABA on the frequency composition of the electrical activity of various brain structures of rats

Abstract

The frequency composition of the electrograms (EG) of the visual area of the cortex and deep brain structures (putamen, dorsal hippocampus, medial portion of the mid-hypothalamus) were investigated in chronic experiments in 36 awake rats under the conditions of the separate and combined introduction of GABA, its agonists (muscimol, baclofen), and an antagonist (bicuculline) into the lateral ventricle of the brain. The principal effects were manifested primarily in the form of a decrease in the power of the oscillations in the 7-16 Hz region of the range (1-25 Hz) of EG frequencies analyzed. Even though these changes were unidirectional following the administration of the agonists, they nevertheless differed with respect to the degree of expressivity in the different structures. Bicuculline, injected against the background of the action of muscimol and baclofen, attenuated the effects induced by them. The possible mechanisms of the phenomena discovered are discussed.