Expression of voltage-gated calcium channel subunits in rat dorsal root ganglion neurons

In the present study, we have used in situ hybridisation to examine the dis tribution of calcium channel subunits in rat dorsal root ganglion (DRG) neu rons. Within DRG neurons, the calcium channel alpha subunit mRNAs alpha (1A ), alpha (1B), alpha (1C), alpha (1D), alpha (1E), alpha (1l) and alpha (1S ) were readily detected in small (< 25 mum), medium (25-45 mum) and large ( > 45 mum) diameter neurons. alpha (1F) was present at very low levels in th ese neurons whilst alpha (1G) was virtually undetectable. The calcium chann el auxiliary subunits alpha (2)delta (1) and alpha (2)delta (2) showed a co mplementary pattern of distribution to that Of alpha (2)delta (3) in DRG ne urons. alpha (2)delta (1) and alpha (2)delta (2) transcripts were expressed predominantly in small c-type sensory neurons and were present at lower le vels in large A beta -type sensory neurons. In contrast, alpha (2)delta (3) mRNA was present in high quantities in the large-diameter cells but was ex pressed at lower levels in small-diameter neurons of the DRG. The present s tudy provides an insight into the molecular profile of calcium channel alph a (1) and alpha (2)delta subunits in the neurons responsible for transmitti ng sensory information. (C) 2001 Elsevier Science Ireland Ltd. All rights r eserved.