The Role of Presynaptic GABAB Receptors in Stimulus-Dependent Disinhibition and the Induction of Long-Term Potentiation
The existence of gamma-aminobutyric acidB (GABAB) autoreceptors regulating GABA release is supported by studies using both synaptosomal preparations (Bonanno et al., 1989a,b; Anderson and Mitchell, 1985) and intact cellular systems (Waldmeier et al., 1988; Harrison et al., 1988; Harrison, 1990). The chapter by Lambert and Harrison (this volume) reviews the electrophysiological data indicating the presence of GABAB autoreceptors. The next step in unraveling the significance of these receptors is to determine their effects on the behavior of neurons in active neural circuits. In this chapter, we demonstrate how stimulus-dependent disinhibition mediated by GABAB receptors enhanced N-methyl-D-aspartate (NMDA) receptor-mediated currents, discuss the evidence that GABAB autoreceptors mediate stimulus-dependent disinhibition, and demonstrate how GABAB-mediated stimulus-dependent disinhibition facilitates long-term potentiation (LTP) and polysynaptic transmission in the hippocampal formation.
KeywordsGranule Cell Dentate Gyrus Mossy Fiber Population Spike Perforant Path
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