Astorga, Guadalupe Bao, Jin Marty, Alain Augustine, George J. Franconville, Romain Jalil, Abdelali Bradley, Jonathan Llano, Isabel 2024-01-20T06:33:45Z 2024-01-20T06:33:45Z 2022-01-25 2015-07 1662-5102 https://pubs.kist.re.kr/handle/201004/125251 While it has been proposed that the conventional inhibitory neurotransmitter GABA can be excitatory in the mammalian brain, much remains to be learned concerning the circumstances and the cellular mechanisms governing potential excitatory GABA action. Using a combination of optogenetics and two-photon calcium imaging in vivo, we find that activation of chloride-permeable GABA(A) receptors in parallel fibers (PFs) of the cerebellar molecular layer of adult mice causes parallel fiber excitation. Stimulation of PFs at submaximal stimulus intensities leads to GABA release from molecular layer interneurons (MLIs), thus creating a positive feedback loop that enhances excitation near the center of an activated PF bundle. Our results imply that elevated chloride concentration can occur in specific intracellular compartments of mature mammalian neurons and suggest an excitatory role for GABA(A) receptors in the cerebellar cortex of adult mice. English FRONTIERS MEDIA SA An excitatory GABA loop operating in vivo Article 10.3389/fncel.2015.00275 1 FRONTIERS IN CELLULAR NEUROSCIENCE, v.9 FRONTIERS IN CELLULAR NEUROSCIENCE 9 N scie scopus 000358790800001 2-s2.0-84937414444 Neurosciences Neurosciences & Neurology Article CEREBELLAR GRANULE CELLS RECEPTORS INHIBITION INTERNEURONS ACTIVATION EXCITABILITY TRANSMISSION STIMULATION DIFFUSION RELEASE calcium GABA cerebellum parallel fibers interneurons