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Acta Physiologica 2010; Volume 200, Supplement 681
Abstracts of the 61st National Congress of the Italian Physiological Society
9/15/2010-9/17/2010
Varese, Italy
ALPHA7 NICOTINIC RECEPTOR ACTIVATION ENHANCES NEUROTRANSMISSION AND PLASTICITY IN THE CEREBELLAR GLOMERULUS
Abstract number: P75
PRESTORI1 F, LOMBARDO1 P, GOSELINK1,3 RJM, DE STEFANO5 ME, BERTRAND4 D, DE ZEEUW3 C, D'ANGELO1,2 E
1Dept Physiology, Univ. of Pavia, Pavia, Italy
2Brain Connectivity Center, Istituto Neurologico IRCCS fondazione C. Mondino, Pavia, Italy
3Dept of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
4Dept of Neuroscience, Centre Mdical Universitaire, Geneve, Switzerland
5Dept of Cellular Biology and Development, La Sapienza Univ., Roma, Italy
The nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels abundantly expressed in the central nervous system, including the cerebellum. nAChRs play important roles in regulating synaptic transmission and neuronal plasticity in various brain regions and changes in their structure and activity are responsible for major brain pathologies. Although nAChRs are found in the cerebellum, their functional effects are still largely unknown. By using in-vivo extracellular field recordings in the cerebellar granular layer of rats (P18-P25), we show that the response to tactile facial stimulation is modulated by local intracerebellar perfusion of nicotinic agents. A theta-sensory stimulus (TSS) induced enhanced LTP in the presence of either nicotine or of the specific alpha7-nAChR agonist choline, but reversed plasticity into LTD in the presence of the alpha7-nAChR antagonist MLA. Similar results were obtained by patch clamp recordings in acute cerebellar slices (P18-P22). Moreover, choline perfusion increased both presynaptic neurotransmitter release and postsynaptic [Ca2+] transients induced by a 100-ms 100-Hz mossy fiber burst. These results are supported by immunogold electron microscopy experiments that revealed both pre- and postsynaptic alpha7-nAChRs at the mossy fiber granule cell synapse. These results argue in favour of an LTD-LTP switch determined by nAChR activation, with potential implication for the gating of learning in the cerebellar granular layer.
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Acta Physiologica 2010; Volume 200, Supplement 681 :P75