RESUMO
Objective To investigate the effects of different concentrations of isoflurane on viability in rat primary cortical neurons. Methods Primary cortical neurons were isolated from neonatal Wistar rats (less than 24 h after birth) and exposed to 0.6 %, 1.2 % and 2.4 % isoflurane for 1, 2, 4, 8, 12 or 24 h, cell viability was evaluated by MTT reduction and LDH release assays. Changes in intracellular [Ca2+]i were detected by real-time confocal microscopy after the neurons were exposed to different concentrations of isoflurane. Results Exposure to 0.6% isoflurane for 24 h significantly increased viability of the primary rat cortical neurons as shown by decrease in LDH release and increase in MTT and elevation of peak [Ca2+]i. Exposure to 1.2% isoflurane for 12 or 24 h and to 2.4% isoflurane for 8, 12 or 24 h significantly reduced viability of cortical neurons associated with high and fast elevation of peak [Ca2 +] i. Conclusion Exposure to 0.6 % isoflurane increases viability of the primary rat cortical neurons. Exposure to 1.2% isoflurane and to 2.4% isoflurane decreases cell viability and the mechanism may be related to the changes in calcium concentrations in the neurons.