Seizure-like activity in hyaluronidase-treated dissociated hippocampal cultures.
The extracellular matrix (ECM) plays an important role in use-dependent synaptic plasticity. Hyaluronic acid (HA) is the backbone of the neural ECM, which has been shown to modulate α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA) receptor mobility, paired-pulse depression, L-type voltage-dependent Ca(2+) channel (L-VDCC) activity, long-term potentiation and contextual fear conditioning. To investigate the role of HA in the development of spontaneous neuronal network activity, we used microelectrode array recording and Ca(2+) imaging in hippocampal cultures enzymatically treated with hyaluronidase. Our findings revealed an appearance of epileptiform activity 9 days after hyaluronidase treatment. The treatment transformed the normal network firing bursts and Ca(2+) oscillations into long-lasting "superbursts" and "superoscillations" with durations of 11-100 s. The changes in Ca(2+) transients in hyaluronidase-treated neurons were more prominent then in astrocytes and preceded changes in electrical activity. The Ca(2+) superoscillations could be suppressed by applying the L-VDCC blocker diltiazem, whereas the neuronal firing superbursts could be additionally suppressed by 6-cyano-7-nitroquinoxaline-2,3-dione as an antagonist of AMPA/kainate receptors. These results suggest that changes in the expression of HA can be epileptogenic and that hyaluronidase treatment in vitro provides a robust model for the dissection of the underlying mechanisms.
Laboratory for Brain Extracellular Matrix Research, Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod, Russia ; Cell Technology Group, Nizhny Novgorod State Medical Academy Nizhny Novgorod, Russia.
Maria
M
Vedunova
Tatiana
T
Sakharnova
Elena
E
Mitroshina
Maya
M
Perminova
Alexey
A
Pimashkin
Yury
Y
Zakharov
Alexander
A
Dityatev
Irina
I
Mukhina
AMPA receptors; Ca2+ imaging; L-type Ca2+ channels; extracellular matrix; hyaluronic acid; microelectrode array; neuronal network; seizure