COLOCALIZATION OF PARVALBUMIN AND CALBINDIN D-28K IN NEURONS INCLUDING CHANDELIER CELLS OF THE HUMAN TEMPORAL NEOCORTEX

Chandelier cells are cortical GABAergic interneurons with a unique syn aptic specificity enabling them to exert a strong inhibitory influence on pyramidal cells. By using immunocytochemistry for the calcium-bind ing protein calbindin D-28k in the human temporal neocortex, we have f ound numerous immunoreactive processes that were identified as chandel ier cell axon terminals. This was a striking find since in previous im munocytochemical studies of the primate neocortex, chandelier cell axo n terminals had been shown to be immunoreactive for another calcium-bi nding protein, parvalbumin, and colocalization studies indicate that p arvalbumin and calbindin are present in almost completely separate neu ronal populations. Here, we present double-label immunofluorescence ex periments showing that parvalbumin and calbindin immunoreactivities ar e colocalized in certain neurons that include a subpopulation of chand elier cells whose cell bodies are located mainly in layers V and VI of the human temporal neocortex. The results suggest a selective laminar distribution of neurochemical subtypes of chandelier cells which is a peculiar feature of the organization of the human neocortex. (C) 1997 Elsevier Science B.V.