of Santa Catarina, Florianopolis, SC, Brazil) and Fredric M. Menger (Emory University, Atlanta, GA, USA)We dedicate this essay to Richard Burnard Rodnight (1921 2012) who published 51 important neurochemistry papers from his laboratory in Porto Alegre, Brazil. It almost defies credulity to realize that he began this work at the age of 65 when he first moved to Brazil from London. He was required to learn Portuguese and make do initially with limited research facilities. His research interests included calcium channels, and it is this topic that we discuss briefly in honor of the great scientist.Richard Rodnight (in memoriam)The key word here is voltage-dependent calcium channels or VDCC. As the name implies, the channels, found in cell membranes, are permeable to calcium ion (about 1000 times more so than to sodium ion). At a resting membrane potential the VDCC is normally closed. But the channels are activated (opened) when the membrane is depolarized, i.e. the charge difference across the membrane is neutralized. This is the origin of the term voltage-dependent. Many interesting things can happen when membranes are electrically depolarized. Calcium ion, normally several thousand times higher in concentration outside the cells than inside, rush into the cells by passive diffusion (discussed in an earlier essay).Excitation of neurons, release of neuron transmitters, and protein phosphorylation are three of the many consequences of this ion movement. Thus, VDCC function represents an important strategy for regulating nerve activity.Cartoon picture of calcium channel (Design by Luciana Afonso)How do gated channels work? The channel is complex combination of proteins, stretched across the cell membrane, the largest of which forms the conduction pore. Different segments of the protein sense the membrane voltage and determine the membrane preference to calcium over sodium. Subunits of the channel complex link the system to various intracellular processes including Ca++ dependent synaptic transmission between nerve cells at various sites including the thalamus.Benzodiazepines, an important class of tranquilizers (used in the treatment of depression, seizures, and panic attack) reduce voltage-gated calcium conductance, and this might be an important mechanism by which the compounds produce their sedative effects. Further understanding of the VDCC regulatory mechanisms may lead to new treatments of neurological disease.Although calcium seems to trigger signaling pathways essential for certain types of memory, excess calcium can actually cause brain damage. For example, the pineal gland can become calcified in conditions such as Alzheimers disease and other types of dementia. Biology is, as always, a delicate balance between too little and too much.References:Descartes Error. Emotion, Reason and the Human Brain. (A. Damasio). ISBN 978-85-359-2200-4.Shepard, M; Lader, M; Rodnight (Deposito legal Z. 719-71).CALCIO E FUNCIONAMENTO DO CEREBRO por Haidi D. Fiedler (Laboratorio de Catalise e Fenomenos Interfaciais, INCT-Catalysis, UFSC, Brasil) e Fredric M. Menger (Emory University, Atlanta, GA, USA)Traduzido por Natanael F. Franca Rocha, Florianopolis, BrasilEste ensaio e dedicado a Richard Burnard Rodnight (1921 - 2012), que publicou 51 artigos importantes sobre neuroquimica durante o tempo que trabalhou em seu laboratorio na cidade de Porto Alegre, RS. E ate dificil de acreditar que ele tenha comecado esse trabalho aos 65 anos de idade, quando