Voltage- and γ-aminobutyric acid-activated membrane currents in the human medulloblastoma cell line MHH-MED-3

The whole-cell patch clamp technique was used to characterize voltage- and neurotransmitter-activated currents in the medulloblastoma cell line MHH-MED-3 and cells from tissue slices and primary cultures of two medulloblastoma biopsies. These preparations revealed similar electrophysiological properties. All tested cells displayed 4-aminopyridine-sensitive delayed rectifying K+ currents, γ-aminobutyric acidA receptor-mediated Cl− currents and most of them inward rectifier K+ currents. Transient inward currents were mainly carried by low-voltage activated T-type Ca2+ channels in MHH-MED-3 cells, and tetrodotoxin-sensitive Na+ channels in cells from the primary culture. From these characteristics we conclude that medulloblastoma cells share physiological features with developing cerebellar granule cells at an immature stage.