*Article* **Failed Neuroprotection of Combined Inhibition of L-Type and ASIC1a Calcium Channels with Nimodipine and Amiloride**

**Jonas Ort 1,\*, Benedikt Kremer 1, Linda Grüßer 2, Romy Blaumeiser-Debarry 2, Hans Clusmann 1, Mark Coburn 3, Anke Höllig 1,**† **and Ute Lindauer 1,**†


Received: 7 November 2020; Accepted: 20 November 2020; Published: 24 November 2020

**Abstract:** Effective pharmacological neuroprotection is one of the most desired aims in modern medicine. We postulated that a combination of two clinically used drugs—nimodipine (L-Type voltage-gated calcium channel blocker) and amiloride (acid-sensing ion channel inhibitor)—might act synergistically in an experimental model of ischaemia, targeting the intracellular rise in calcium as a pathway in neuronal cell death. We used organotypic hippocampal slices of mice pups and a well-established regimen of oxygen-glucose deprivation (OGD) to assess a possible neuroprotective effect. Neither nimodipine (at 10 or 20 μM) alone or in combination with amiloride (at 100 μM) showed any amelioration. Dissolved at 2.0 Vol.% dimethyl-sulfoxide (DMSO), the combination of both components even increased cell damage (*p* = 0.0001), an effect not observed with amiloride alone. We conclude that neither amiloride nor nimodipine do offer neuroprotection in an in vitro ischaemia model. On a technical note, the use of DMSO should be carefully evaluated in neuroprotective experiments, since it possibly alters cell damage.

**Keywords:** neuroprotection; neural injury; nimodipine; subarachnoid haemorrhage; acid-sensing ion channels; amiloride; oxygen-glucose deprivation
