Regional expression of a MCD-peptide and dendrotoxin I-sensitive voltage-dependent potassium channel in rat brain.

In situ hybridization histochemistry has been used to analyze the regional expression of a class of voltage-dependent K+ channel that is sensitive to two polypeptide toxins (MCD peptide and dendrotoxin I) that produce spectacular effects on brain function. A heterogeneous expression of this K+ channel was observed throughout the brain. High mRNA contents were observed in the granule cells of the gyrus dentatus as well as in pyramidal cells of the Ammon horn (CA3 greater than CA1) and in the cerebellum. Conversely, low levels of expression were found in basal ganglia (caudate putamen, globus pallidus, and ventral pallidum).