1
Laboratory of Molecular Neurobiology, Mitsubishi Kasei Institute of Life Sciences and CREST (Japan Science and Technology), 11 Minamiooya, Machida-shi, Tokyo 194-8511, Japan
2
Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
A single neurotransmitter elicits diverse physiological responses through activation of multiple receptor subtypes and/or heterosynaptic interactions involving distinct synaptic targets. We found that a typical excitatory transmitter released from the climbing fiber (CF) in the cerebellar cortex not only excited Purkinje cells directly but also presynaptically inhibited GABAergic transmission from interneurons converging on the same Purkinje cells. Both homosynaptic and heterosynaptic actions of the CF transmitter (possibly glutamate) were mediated by activation of AMPA receptors. Dual AMPA receptor-mediated functions of excitation and disinhibition may ensure transmission of cerebellar CF signals controlling sensorimotor coordination.
