Regional and cellular distribution of neural visinin-like protein immunoreactivities (VILIP-1 and VILIP-3) in human brain

Neural visinin-like proteins (VILIPs) are members of the neuronal subfamily of intracellular EF-hand calcium sensor proteins termed the NCS family, wh ich are thought to play important roles in cellular signal transduction. Wh ile numerous studies suggest a wide but uneven distribution of these protei ns in rat and chicken brain, their location in, and possible significance f or, the human brain, remains to be established. We used specific polyclonal antisera to map the human brain for VILIP-1 and VILIP-3 immunoreactivities . VILIP-1 was detected in cortical pyramidal cells and interneurons, septal , subthalamic and hippocampal neurons (subfields CA1 and CA4 pyramidal cell s and especially hilar interneurons) as well as in cerebellar Golgi, basket , granule, stellate and dentate nucleus neurons. Purkinje cells were free o f immunoreaction. VILIP-3 was more restricted in its distribution. It was i dentified in cerebellar Purkinje cells and a subpopulation of granule neuro ns. Further, neurons belonging to different nuclei of the brain stem and mu ltiple subcortical nerve cells stained for visinin-like protein 3. A weak i mmunoreaction appeared in cortical and hippocampal neurons. Intracellularly the immunoreactivity appeared in the perikarya, dendrites and some axons. Sometimes, immunostaining was found in the neuropil. Glia did not express v isinin-like proteins. Our findings support, from a neuroanatomical viewpoin t, the idea that these calcium sensor proteins may be of relevance for neur onal signalling in the human CNS.