Increased calcium influx triggers and accelerates cortical spreading depression in vivo in male adult rats

- We topically applied ionophore A23187 in rat cortex to increase calcium influx.
- This ionophore (10-100 μM) dose-dependently accelerates spreading depression (CSD).
- Topical application of a much higher dose of this compound (2 mM) triggers CSD.
- Increased Ca2+ influx is suggested as a key element in the CSD induction mechanism.
- Data stimulate and justify further experiments on brain disorders related to CSD.

Cortical spreading depression (CSD) is a depolarization wave associated with neurological disorders such as migraine, cerebral ischemia and traumatic brain injury. The mechanism of action of this phenomenon still remains unclear. Although it is suggested that extracellular K+ accumulation contributes to CSD, other ions may play a relevant role in the mechanism of propagation of the wave. In this context, we hypothesize that Ca2+ may play an important function in the wave propagation. Our results demonstrate that enhancing Ca2+ influx into the cells by topical cortical application of the ionophore A23187 (10 μM, 50 μM and 100 μM solutions) increases the velocity of CSD propagation in a dose-dependent manner, and a much higher dose of this compound (2 mM) triggers CSD. In conclusion, increased Ca2+ influx can be a key element in the induction mechanism of the CSD, and should be assessed in further experimental strategies targeting brain disorders related to CSD.