24 - Interspecies Comparison of Expression of GABA/Benzodiazepine Receptors and their Subunits in the Motor and Limbic Nuclei of the Thalamus

Abstract

This chapter presents an overview on the current knowledge on the organization of γ-aminobutyric acid (GABA)ergic mechanisms in the thalamus based on the literature data and findings on the motor and limbic thalamic nuclei in the cat and monkey. In the monkey thalamus, there is a greater variety of GABAergic synapses and the internuclear differences are more pronounced compared to the thalami of rat and cat. Additionally, in the monkey ventro-lateral nucleus, GABAergic dendro-dendritic contacts between local circuit neurons are found commonly but in the ventral anterior nucleus, they are absent. The chapter also explores whether there are functional differences among the various types of GABAergic synapses found in thalamic nuclei. The data described in the chapter suggests that different mechanisms of modulation of GABAergic transmission can exist in the thalami of different species, and if this is the case, the physiological properties of otherwise similar afferent inputs can differ as well.