DY-9760e, a Novel Calmodulin Antagonist, Reduces Infarction after Permanent Focal Cerebral Ischemia in Rats

Abstract

DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate), a novel calmodulin antagonist, provides effective protection against Ca²⁺ ionophore-induced cytotoxicity and brain injury induced by transient focal ischemia. In this study, we evaluated the effect of DY-9760e on ischemic infarct volume in rats subjected to permanent focal ischemia. DY-9760e (0.5 mg/kg/h for 6 h) significantly reduced the infarct volume when administered immediately after middle cerebral artery occlusion. Furthermore, this neuroprotection was also exerted by treatment with a 3-hour delay, implying that the therapeutic time window for this compound is at least 3 h. In addition, although treatment with 0.1 mg/kg/h for 24 h was ineffective, the combination of a loading dose of 0.3 mg/kg/h for 2 h followed by 0.1 mg/kg/h for 22 h yielded a significant reduction in infarct volume. Thus, prolonged infusion preceded by a loading dose is an efficacious dosing regimen for DY-9760e, especially at a low infusion rate. These data demonstrate the substantial neuroprotective effect of DY-9760e in a permanent focal ischemia model and indicate that this neuroprotectant may be of therapeutic value for the treatment of acute stroke.

DY-9760e, a Calmodulin Antagonist, Reduces Brain Damage after Permanent Focal Cerebral Ischemia in Cats

“…31) We have developed DY-9760e, a calmodulin antagonist, which exerts neuroprotective action against cell death induced by Ca 2ϩ overload 15,17) and ameliorates brain injury that occurs after cerebral ischemia in rodents. [18][19][20][21][22]32,33) The present study demonstrates that DY9760e reduces the infarct volume in cats with permanent MCA occlusion, and this finding is consistent with previous studies in rats with permanent MCA occlusion, extending the observation into a gyrencephalic species. 20,21) Focal ischemia models can be categorized mainly into two types: permanent and transient.…”

“…[18][19][20][21][22]32,33) The present study demonstrates that DY9760e reduces the infarct volume in cats with permanent MCA occlusion, and this finding is consistent with previous studies in rats with permanent MCA occlusion, extending the observation into a gyrencephalic species. 20,21) Focal ischemia models can be categorized mainly into two types: permanent and transient. Although both types of focal ischemia can occur in stroke patients, clinically the majority of strokes do not reperfuse in the first 24 h. 34) Furthermore, the Stroke Therapy Academic Industry Roundtable stated that novel compounds should show efficacy in species larger than rodents.…”

“…15,17) DY-9760e is also capable of reducing the ischemic infarct volume when given up to 3 h after the onset of permanent MCA occlusion in rats. 20) Given a previous report showing that the Ca 2ϩ -bound calmodulin complex reaches maximal levels 4 h following cerebral ischemia, it is feasible that the therapeutic time window for DY-9760e is 3 h. 12) Taken together, it is plausible that the amelioration of ischemic brain injury with this drug is mediated by a calmodulin antagonistic action in the brain. Further studies are needed to evaluate the molecular mechanism by which this compound exerts neuroprotective functions.…”

“…[15][16][17] This compound ameliorates brain injury that occurs after transient or permanent focal ischemia and microembolization in rats. [18][19][20][21][22] Although these studies in various rodent models show a hopeful characteristic of DY-9760e, it is subsequently important to assess if it exerts a protective effect in a large animal model of focal cerebral ischemia. Cats, a gyrencephalic species in common with humans, have long been used both in pathophysiological studies for cerebral ischemia and in investigations for the protective efficacy of agents.…”

Protective Effect of DY-9760e, a Calmodulin Antagonist, against Neuronal Cell Death

“…14) We have developed a competitive calmodulin antagonist, 3-[2-[4-(3-chloro-2-methylphenylmethyl)-1-piperazinyl]-ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate (DY-9760e), which exerts a cytoprotective action against the cell death induced by a Ca 2ϩ ionophore 15) and ameliorates brain injury that occurs after transient and permanent focal ischemia in rats. [16][17][18][19] Since DY-9760e does not alter cerebral blood flow (CBF) following focal ischemia, 17) it may produce the neuroprotection against cerebral ischemia via mechanisms other than the improvement of CBF. To further clarify the neuroprotective properties of DY-9760e, using rat primary cultured neurons, we evaluated the effect of the drug on the neuronal cell death elicited by cell-toxic stimuli that mimic cellular events observed in cerebral ischemia.…”