High affinity and low affinity heteromeric nicotinic acetylcholine receptors at central synapses.
Most neuronal heteromeric nicotinic receptors seem able to adopt two different stochiometries depending on the ratio of α and β subunits. In recombinant receptors these two stoichiometries have been associated with different affinities to ACh, but it is not known which stoichiometry is present at nicotinic synapses in the nervous system. One possible clue to this identification is the speed of decay of the synaptic currents. In many ionotropic receptors this speed has been linked to the dissociation rate of the transmitter, which is itself related to its affinity. On this basis we propose that, at the synapse between motoneuron and Renshaw cells, the heteromeric nicotinic receptors are mostly low affinity receptors and suggest that, in contrast, the very slow decay of some synaptic currents recorded in other parts of the brain signs the presence of high affinity receptors rather than volume transmission.
Center for Neurophysics, Physiology, Pathology, CNRS UMR 8119, Université Paris Descartes 45 rue des Saints Pères, Paris, 75006, France boris.lamotte-incamps@parisdescartes.fr.
Boris Lamotte
BL
d'Incamps
Laboratory of Cerebral Physiology, CNRS UMR 8118, Université Paris Descartes 45 rue des Saints Pères, Paris, 75006, France.
Philippe
P
Ascher
D000818:Animals; D001921:Brain / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D009046:Motor Neurons / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology
D011978:Receptors, Nicotinic