Jan van der Valk

A plea to reduce or replace fetal bovine serum in cell culture media

To the Editor,Fetal bovine serum (FBS) is a universal growthsupplement of cell and tissue culture media. FBS is anatural cocktail of most of the factors required for cellattachment, growth, and proliferation, effective formost types of human and animal (including insect)cells. Although in use for more than 50 years, FBS hasnever been fully characterized. Recent proteomic andmetabolomic studies revealed approx. 1,800 proteins(Anderson and Anderson 2002; Anderson et al. 2004)and more than 4,000 metabolites (Psychogios et al.2011) present in serum. However, the use of serum incell culture also bears a number of disadvantages.These disadvantages can either be seen from: (a) ascientific, cell biological point of view, since serum ingeneral is an ill-defined mixture of components inculture media, with qualitative and quantitative,geographical and seasonal batch-to-batch variations,(b) from biosafety aspects, since FBS may containadverse factors, like endotoxin, mycoplasma, viralcontaminants or prion proteins, (c) from ethicalperspectives in terms of animal protection argumentsregarding the harvest and collection of FBS frombovine fetuses, and (d) in terms of recent concernsabout the global supply versus demand of FBS. As aconsequence, a number of strategies were developedto reduce or replace the requirement for FBS in cellculture media.FBS is a by-product of the beef packing industry.Thus, the supply is dictated by many factors, includingbeef consumption, dairy product consumption, feedprices, environmental factors such as drought, cattleimport and export, governmental farm policies (Sha-iler and Corrin 1999), and the outbreak of diseases(foot and mouth disease, BSE) (Asher 1999; Dormont1999; Even et al. 2006; Wessmann and Levings ).The availability of FBS has changed dramatically overthe past few years (Fujimoto 2002). Therefore, allefforts and attemptsshouldbe undertaken toovercomethe expected shortfall in FBS supply. In the case ofFBS, supply versus demand models do not followtypical economic principles. Normally, supply can beadjusted to meet the demand. However, in case ofFBS, supply and demand operate independently ofeach other. In addition, there is a severe geographicalmismatch between the supply of and the demand forFBS. Demand is highest in US and Europe, while themajor sources of FBS are far away—in Brasil,Argentina, South Africa, Australia, New Zealand,and Central America, since in those countries huge

Glutamate-induced inward current in a clonal neuroblastoma cell line

The presence of glutamate-induced electrophysiological responses was examined in eight clonal neuroblastoma cell lines with the whole-cell voltage clamp technique. Only N2A cells responded to glutamate superfusion with a concentration-dependent, reversible inward current. Superfusion with the analogues kainic acid, quisqualic acid and N-methyl-D-aspartic acid also evoked inward currents but they had a smaller amplitude. The results indicate that N2A neuroblastoma cells could serve as an in vitro model to study the functional properties of glutamate receptors and associated ion channels.

L- and T-type calcium channels in cultured neuronal cell lines are insensitive to tetanus toxin

Possible effects of tetanus toxin (TeTox) on voltage-activated Ca2+ channels of the mouse neuroblastoma cell line N1E-115 and of the neuroblastoma x glioma hybrid cell line NG108-15 have been investigated using the whole-cell voltage clamp technique. Similar to N1E-115 cells, differentiated NG108-15 cells express transient (T-type) as well as long-lasting (L-type) Ca2+ channels. Using various treatment protocols N1E-115 and NG108-15 cells were exposed to TeTox externally and by internal dialysis. In the cells treated with TeTox normal Ca2+ channel activity was present, as measured by the voltage-activated Ba2+ currents under voltage clamp conditions. In addition, intracellular microelectrode recordings showed that TeTox did not block the Ca2+ action potential in N1E-115 cells. It is concluded that TeTox, in contrast to previously reported results, does not affect voltage-activated T- and L-type Ca2+ channels in cultured neuronal cell lines. The results also indicate that Ca2+ channel block is unlikely to be an explanation for the block of neurotransmitter release by TeTox in vivo.

Chronic sabeluzole treatment of cultured rat cerebellar granule cells reduces N-methyl-D-aspartate-induced inward current

The effects of sabeluzole, a drug that protects rat hippocampal neurones from glutamate- and N-methyl-D-aspartate (NMDA)-induced toxicity, were investigated in rat cerebellar granule cells in vitro with the whole-cell voltage clamp technique. Acute exposure of 0.1 microM sabeluzole for 20 min prior to experiments did not significantly affect glutamate receptor-mediated inward currents. Conversely, exposure of cultured granule cells to sabeluzole for 7 days reduced the NMDA-induced inward current and did not affect the non-NMDA responses evoked by kainic acid. The results suggest that chronic treatment with sabeluzole selectively reduces the functional NMDA response.