Calcium oscillations in freshly isolated neonatal rat cortical neurons.

AIM

To investigate the mechanisms of intracellular calcium concentration ([Ca2+]i) oscillations in freshly isolated neonatal rat cortical neurons.

METHODS

Cortical neurons were isolated from neonatal rats 6-7 d after birth by enzymatic digestion. [Ca2+]i changes were measured in a microscopic calcium measurement system with Fura-2 as indicator.

RESULTS

In a total of 82 neurons recorded, 47 showed spontaneous [Ca2+]i oscillations. The spontaneous [Ca2+]i oscillations were dependent on [Ca2+]o. Removal of [Ca2+]o completely abolished spontaneous oscillations. Tetraethylammonium 1 mmol/L increased both the amplitude and frequency of calcium oscillations, whereas the frequency was increased by Cs+ 1 mmol/L. Ba2+ 1 mmol/L, in contrast, induced [Ca2+]i oscillations superimposed on a sustained phasic increase.

CONCLUSION

Spontaneous [Ca2+]i oscillation is an intrinsic property of neonatal rat cortical neurons. Potassium channels play an important role in the control of both the amplitude and frequency of [Ca2+]i oscillations in cortical neurons.