Large clusters of alpha7-containing nicotinic @entity934 receptors on XXXX spinal cord neurons.

@entity1573 @entity460 @entity934
Nicotinic @entity934 receptors containing the alpha7 gene product are widely expressed in the nervous system and have high @entity460 permeabilities that allow them to influence numerous @entity460 -dependent processes. Though often found at presynaptic locations, where they enhance transmitter release, the receptors can also occupy postsynaptic sites. Highest levels have been reported for @entity1573 ciliary ganglion neurons, where the postsynaptic receptors are concentrated on somatic spines arranged in clumps and appear as large receptor clusters. We show here that subpopulations of @entity1573 spinal cord neurons also express high levels of alpha7-containing receptors and arrange them in large clusters. The populations include peripheral motoneurons, presumptive preganglionic neurons, neurons adjacent to the lateral motor column, and possible interneurons in the ventral horn. In many cases, the receptor clusters codistribute with filamentous actin, as do clusters on ciliary ganglion neurons, where the actin represents a somatic spine constituent. In other respects, the spinal cord clusters differ. Those on motoneurons codistribute with the actin-associated component drebrin, as do the clusters on ciliary ganglion neurons, but the clusters on preganglionic neurons do not. Preganglionic neurons do, however, stain for lipid raft components as found for ciliary ganglion neurons, where the rafts embed the receptor-enriched spines. The results demonstrate that CNS neurons can configure alpha7-containing nicotinic receptors into large clusters but also suggest that the clusters are not likely to reflect a common molecular substructure on all neurons.
