We have previously reported that
dauricine protects brain tissues from focal
cerebral ischemia. To corroborate this effect, neurotoxicity due to
hypoxia and
hypoglycemia was assessed in primary cultures of rat cortical neurons by using a
trypan blue exclusion method. To further clarify the mechanism, the intracellular Ca2+ concentration ([Ca2+]i) and mitochondrial membrane potential (Deltapsim) of dissociated rat cortical cells were monitored by
fura-2 fluorescence measurements and flow cytometry, respectively. The results showed that 1 and 10 micromol/L
dauricine significantly enhanced neuronal survival during 4 h of
hypoxia and
hypoglycemia.
Dauricine inhibited the increase in [Ca2+]i and decrease in Deltapsim induced by 30 min of
hypoxia and
hypoglycemia. When exploring the pathway, we found that 1 micromol/L
dauricine inhibited the [Ca2+]i increase induced by 7.5 nmol/L
thapsigargin in either the presence or absence of extracellular Ca2+ and by 1 mmol/L
L-glutamate in the presence of extracellular Ca2+. These results suggest that
dauricine prevents neuronal loss from
ischemia in vitro, which is in accordance with our previous research in vivo. In addition, by inhibiting Ca2+ release from the endoplasmic reticulum and Ca2+ influx from the extracellular space,
dauricine suppressed the increase in [Ca2+]i and, subsequently, the decrease in Deltapsim induced by
hypoxia and
hypoglycemia. This effect may underlie the mechanism of action of
dauricine on
cerebral ischemia.