Synaptic plasticity

Experience strengthening transmission by driving AMPA receptors into synapses. Takahashi, T. et al. Science 299, 1585–1588 (2003)

Experiments in vitro had shown that the glutamate receptor subunit GluR1 is incorporated into synapses as a result of plastic changes. Does the same mechanism operate in vivo? The authors transfected neurons of the rat barrel cortex with GluR1 and found this to be the case, but only if the whiskers were not trimmed or a segment of GluR1 that inhibits delivery of the whole protein to synapses was not co-transfected. So, GluR1 incorporation into the synapse is a mechanism, first identified in slices, which might mediate the effect of experience on the efficacy of synaptic transmission in vivo.

Cell Biology of the Neuron

The presynaptic active zone protein Bassoon is essential for photoreceptor ribbon synapse formation in the retina. Dick, O. et al. Neuron 37, 775–786 (2003)

Functional inactivation of a fraction of excitatory synapses in mice deficient for the active zone protein Bassoon. Altrock, W. D. et al. Neuron 37, 787–800 (2003)

Two papers on the function of the presynaptic protein Bassoon. In the mouse retina, Dick et al. found that the absence of Bassoon led to abnormalities in the formation of ribbon synapses; the presynaptic 'ribbon' is not anchored to the active zone. In the hippocampus, Altrock et al. found that Bassoon is not crucial for synapse formation, but its absence causes reduced transmitter release at a subset of synapses; although synaptic vesicles are docked, they seem unable to fuse.

Sensory Systems

Combinatorial coexpression of neural and immune multigene families in mouse vomeronasal sensory neurons. Ishii, T. et al. Curr. Biol. 13, 394–400 (2003)

Functional expression of murine V2R pheromone receptors involves selective association with the M10 and M1 families of MHC class Ib molecules. Loconto, J. et al. Cell 112, 607–618 (2003)

Two studies showing that neurons of the basal vomeronasal organ (VNO), which express V2R pheromone receptors, also express molecules of the major histocompatibility complex (MHC). Both studies show that VNO neurons that express a given V2R receptor might express several different MHC molecules. In addition, Loconto et al. show that the MHC molecules form a complex with pheromone receptors and β2-macroglobulin, and might be involved in the transport of V2R receptors to the membrane. These data point to a potential role for MHC molecules in pheromone detection.