EN
Cultured hippocampal cells are commonly used as a convenient model but non-physiological conditions (impaired homeostasis, lack of glial cells etc.) persisting over long period of time raise concerns. Acute brain slices are believed to better maintain the physiological features but are often problematic for technical reasons (e.g. complicated access to neurons, attenuated spread of pharmaceutics). Non-physiological conditions in cell cultures during maturation of GABAergic and glutamatergic systems may alter expression of GABAA and glutamate receptors affecting thus the excitation to inhibition balance. Proportion between GABA and glutamate receptors may be evaluated by determining ratio between amplitudes of current responses to saturating agonist concentrations. We have recorded current responses to ultrafast applications of saturating GABA and glutamate concentrations in hippocampal cell cultures (9–15DIV) and in brain slices from CA1 pyramidal neurons of P19–P23 rats. For cell cultures, GABAergic and glutamergic currents ratio was 2.34 ± 0.45 (n=12) while for the brain slices it was only 0.24 ± 0.02 (n=5). These results provide evidence that non-physiological conditions in cell cultures may cause a dramatic change in expression pattern of GABAA and glutamate receptors. The underlying mechanisms are not known, but we may hypothesize that a homeostatic modulation due accumulation of neurotransmitters in culture medium could be involved. Support: grant no. 070231/Z/03/Z.