Voltage-gated calcium channels (VGCCs) within sensory neurones are believed to perform an important role in neuropathic pain. In the present study we examine the changes in VGCC mRNA which occur following streptozocin- (STZ) induced diabetic neuropathy using in situ hybridization. STZ caused a significant increase in alpha(2)delta(1), alpha(2)delta(2), and alpha(2)delta(3) mRNA levels in all neuronal cell types. Similarly, mRNA levels of alpha(1F), alpha(1I), and alpha(1S) were increased in all cell types studied whilst alpha(1A) and alpha(1G) mRNAs were specifically upregulated in medium and large diameter neurones. In conclusion, we demonstrate that the induction of diabetic neuropathy is associated with dramatic changes in the expression of VGCCs.