Neuronal localization of Ca(v)1.2 L-type calcium channels in the rat basolateral amygdala

L-type high-voltage-activated calcium channels are involved in the conduction and integration of electrical activity and associative long-term potentiation in the basolateral amygdalar complex (BLC). However, little is known about the neuronal localization of these channels in this brain region. We used immunohistochemical techniques to determine which cell types in the BLC express the Ca(v)1.2 subtype of L-type calcium channels. Immunofluorescence experiments demonstrated that Ca(v)1.2 calcium channels were mainly found in somata and dendrites of pyramidal neurons that exhibited immunoreactivity for calcium/calmodulin-dependent protein kinase II (CaMK). Only a few parvalbumin-positive and calretinin-positive interneurons exhibited Ca(v)1.2 immunoreactivity. The presence of high levels of Ca(v)1.2 immunoreactivity in BLC pyramidal cells is consistent with physiological findings showing that calcium entry through L-type calcium channels in pyramidal cell dendrites in the lateral amygdala is required for associative LTP and the conversion of synaptic events into long-term emotional memory.