Improved posthypoxic recovery in vitro on treatment with drugs used for secondary stroke prevention

Besides aspirin several new drugs for inhibition of platelet aggregation and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibition are used in secondary stroke prevention. Pharmacology and clinical effects, however, are not fully explained by current understanding of underlying mechanisms. Population spike amplitude (PSAP), an established marker of slice integrity, was measured during hypoxia and recovery thereof in hippocampal slices from control CD1 mice (25-35 g) and animals pretreated in vivo with a single i.p. injection of clopidogrel, ticlopidine, or atorvastatine at different time intervals and dosages. Posthypoxic recovery of PSAP was 20 +/- 35% in control CD1 mice. Upon pretreatment with clopidogrel (1-24 h, 0.5-2 mg/kg body weight) an increase up to 81 +/- 20% (p < 0.01 to control) was observed at 1h interval and 1mg/kg. Application of ticlopidine (1-24 h, 1-4 mg/kg body weight) resulted in an improvement of posthypoxic recovery to 61 +/- 41% (p < 0.05 to control) while administration of atorvastatine (1-24 h, 1-4 mg/kg body weight) caused an increase up to 87 +/- 31% (p < 0.01 to control) at 1h interval and 2 mg/kg. On application of these substances in vitro the NADH autofluorescence spectrum in hippocampal slices is blue-shifted suggesting an alteration of oxidative metabolism. The present data demonstrate a shared neuroprotective effect of agents known to inhibit platelets (acetylsalicylic acid, clopidogrel, and ticlopidine) and HMG-CoA reductase (atorvastatine). The time course of this neuroprotective action in the current experimental study (onset within an hour, duration of several hours in contrast to several days) resembles clinical practice in dosing these substances. We hypothesize that an increase of hypoxic tolerance resulting from mild mitochondrial inhibition by these substances is a principal constituent of the effectiveness of these drugs.