Broad-spectrum cation channel inhibition by LOE 908 MS reduces infarct volume in vivo and postmortem in focal cerebral ischemia in the rat.

Cation channels conduct calcium, sodium and potassium, cations that are likely deleterious in the evolution of focal ischemic injury. We studied the effects of a novel, broad-spectrum inhibitor of several cation channels, LOE 908 MS, on acute ischemic lesion development with diffusion-weighted magnetic resonance imaging (DWI) and on cerebral perfusion with perfusion imaging (PI) in vivo and on cerebral infarct size using 2,3,5-triphenyltetrazolium chloride (TTC) staining postmortem. A total of 18 male Sprague-Dawley rats underwent 90 min of middle cerebral artery occlusion (MCAO) and were randomly and blindly assigned to either LOE 908 MS or vehicle starting 30 min after inducing focal ischemia and continuing for 4 h. Whole-brain DWI and multislice PI were done before initiation of treatment and repeated frequently for the next 3.5 h. DWI-derived lesion volume at 4 h showed a significant difference in favor of the drug treated group (P=0.03), whereas PI-derived perfusion deficit volumes did not significantly differ between the groups. The postmortem infarct volume at 24 h was significantly attenuated in the treated group in comparison to controls (P=0.0001) and neurological score was significantly better in the treated group (P<0.02). Blocking several distinct cation channels with LOE 908 MS significantly reduced infarct size and improved neurological outcome without observable adverse effects in this focal ischemia model.

A glycine site antagonist ZD9379 reduces number of spreading depressions and infarct size in rats with permanent middle cerebral artery occlusion.

Spreading depressions (SDs) occur in experimental focal ischemia and contribute to lesion evolution. N-methyl-D-aspartate (NMDA) antagonists inhibit SDs and reduce infarct size. The glycine site on the NMDA receptor complex offers a therapeutic target for acute focal ischemia, potentially devoid of many side effects associated with competitive and non-competitive NMDA antagonists. We evaluated the effect of the glycine antagonist, ZD9379, on SDs and brain infarction. Male Sprague-Dawley rats (n = 18) weighing 290 to 340 g undergoing permanent middle cerebral artery occlusion (MCAO) were randomly and blindly assigned to receive drug or placebo: Group 1 (pre-MCAO treatment group, n = 5) a 5 mg/kg bolus of ZD9379 over 5 minutes followed by 5 mg/kg/hour drug infusion for 4 hours beginning 30 minutes before MCAO; Group 2 (post-MCAO treatment group, n = 7) a 5 mg/kg bolus of ZD9379 30 minutes after MCAO followed by 5 mg/kg/hour drug infusion for 4 hours; and Group 3 (control group, n = 6) vehicle for 5 hours beginning 30 minutes before MCAO. SDs were monitored electrophysiologically for 4.5 hours following MCAO by continuous recording of cortical direct current (DC) potentials and electrocorticogram (ECoG). Infarct volume was measured 24 hours after MCAO by 2,3,5 triphenyltetrazolium chloride (TTC) staining. Corrected infarct volume was 90 +/- 72 mm3 (mean +/- standard deviation) in Group 1, 105 +/- 46 mm3 in Group 2, and 226 +/- 41 mm3 in Group 3 (P < .001). The corresponding numbers of SDs in the 3 groups were 8.2 +/- 5.8, 8.1 +/- 2.5, and 16.0 +/- 5.1, respectively (P < .01). When all animals (n = 18) were analyzed, infarct volumes and the number of SDs were significantly correlated (r = .68, P = .002). This study demonstrated that ZD9379 initiated before or after MCAO significantly reduced the number of SDs and infarct volume in a permanent focal ischemia model, implying that ZD9379 is neuroprotective and its neuroprotective effect may be related to inhibiting ischemia-related SDs.

Broad-spectrum cation channel inhibition by LOE 908 MS reduces infarct volume in vivo and postmortem in focal cerebral ischemia in the rat.

Cation channels conduct calcium, sodium, and potassium, cations that are likely deleterious in the evolution of focal ischemic injury. Diffusion-weighted magnetic resonance imaging (DWI) is a powerful tool for evaluation of acute cerebral ischemia. We studied the effects of a novel, broad-spectrum inhibitor of several cation channels, LOE 908 MS, on acute ischemic lesion development with DWI and on cerebral infarct size using 2,3,5-triphenyltetrazolium chloride (TTC) staining postmortem. Eighteen male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) and were randomly and blindly assigned to either LOE 908 MS (1 mg/kg bolus 30 min after MCAO and continuous i.v. infusion of 10 mg/kg for 4 h thereafter) or vehicle. Whole-brain DWI was done before initiation of treatment and repeated every 30 min for the next 3.5 h. The animals were reperfused in the magnetic resonance imaging (MRI) scanner 90 min after MCAO. At 24 h, the animals were killed, and the brains were cut into six 2-mm-thick slices and stained with 2% TTC. Percent hemispheric lesion volume (%HLV) was calculated for each animal. Physiological parameters, body weight, and premature mortality (3 in the placebo group and 1 in the treated group) did not differ between the groups. No hypotension, abnormal behavior, or other adverse effects were seen. Pretreatment, the DWI-derived %HLV did not differ between the groups (19.8 +/- 6.2 in the control group and 17.9 +/- 7.9 in the treated group), whereas at 4 h after MCAO, it was significantly smaller in the treated group (21.8 +/- 15.4 vs 40.4 +/- 15.5, p = 0.03). Postmortem, TTC-derived %HLV was significantly attenuated in the LOE 908 MS group (21.3 +/- 11.9 vs 50.1 +/- 10.7, p = 0.0001) and the neurological scores at 24 h were significantly better among the treated rats (2.1 +/- 1.5 vs 4.0 +/- 1.0, p < 0.02). LOE 908 MS significantly improved neurological outcome and reduced infarct size without observable effects in rats as demonstrated in vivo by DWI and confirmed postmortem by TTC staining. Blocking several distinct cation channels by LOE 908 MS showed significant neuroprotection.

A glycine site antagonist, ZD9379, reduces number of spreading depressions and infarct size in rats with permanent middle cerebral artery occlusion.

BACKGROUND AND PURPOSE: Spreading depressions (SDs) occur in experimental focal ischemia and contribute to lesion evolution. N-Methyl-D-aspartate (NMDA) antagonists inhibit SDs and reduce infarct size. The glycine site on the NMDA receptor complex offers a therapeutic target for acute focal ischemia, potentially devoid of many side effects associated with competitive and noncompetitive NMDA antagonists. We evaluated the effect of the glycine antagonist ZD9379 on SDs and brain infarction. METHODS: Male Sprague-Dawley rats (n = 18) weighing 290 to 340 g undergoing permanent middle cerebral artery occlusion (MCAO) were randomly and blindly assigned to receive drug or placebo: group 1 (pre-MCAO treatment group; n=5), a 5-mg/kg bolus of ZD9379 over 5 minutes followed by 5 mg/kg per hour drug infusion for 4 hours beginning 30 minutes before MCAO; group 2 (post-MCAO treatment group; n=7), a 5-mg/kg bolus of ZD9379 30 minutes after MCAO followed by 5 mg/kg per hour drug infusion for 4 hours; and group 3 (control group; n=6), vehicle for 5 hours beginning 30 minutes before MCAO. SDs were monitored electrophysiologically for 4.5 hours after MCAO by continuous recording of cortical DC potentials and electrocorticogram. Infarct volume was measured 24 hours after MCAO by 2,3,5-triphenyltetrazolium chloride staining. RESULTS: Corrected infarct volume was 90+/-72 mm3 (mean+/-standard deviation) in group 1, 105+/-46 mm3 in group 2, and 226+/-40 mm3 in group 3 (P<.001). The corresponding numbers of SDs in the three groups were 8.2+/-5.8, 8.1+/-2.5, and 16.0+/-5.1, respectively (P<.01). When all animals (n=18) were analyzed, infarct volumes and the number of SDs were significantly correlated (r=.68, P=.002). CONCLUSIONS: This study demonstrated that ZD9379 initiated before or after MCAO significantly reduced the number of SDs and infarct volume in a permanent focal ischemia model, implying that ZD9379 is neuroprotective and its neuroprotective effect may be related to inhibiting ischemia-related SDs.