Neurons in the lateral amygdala (LA) receive glutamatergic sensory input from the auditory thalamus and auditory cortex, and these inputs can be modulated by serotonin (5-HT). In the present study, we examined whether serotonergic inhibition of glutamatatergic excitation in the LA occurs via activation of GABAergic interneurons. Single-unit extracellular activity in the LA was recorded in response to iontophoretically applied glutamate. Concurrent application of 5-HT reduced the number of glutamate-evoked action potentials in the majority of neurons tested. GABA antagonists were then iontophoresed with both glutamate and 5-HT. Of the neurons that were inhibited by 5-HT, concurrent application of the GABA antagonists significantly reversed this effect. Application of the GABA antagonists alone had little or no effect on basal neuronal activity. We conclude that the 5-HT-induced inhibition of glutamatergic activity occurs in part through activation of serotonergic receptors on GABAergic interneurons.
|Original language||English (US)|
|Journal||The Journal of neuroscience : the official journal of the Society for Neuroscience|
|State||Published - Jun 1 1999|
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