The effect of the calcium antagonist nimodipine on the gerbil model of experimental cerebral ischemia.

Abstract

SUMMARYThe gerbil model was used to assess the therapeutic effects of the calcium antagonist nimodipine on cerebral ischemia. Transient cerebral ischemia was produced hi each gerbil by bilateral common carotid occlusion of 10-, 15-or 20-mln duration. Nimodipine (0.01 or 0.1 mg/kg) was administered intraperitonealry just before the carotid occlusion or 10-30 min after the removal of the arterial clips. Morbidity of each animal was evaluated using the stroke index, and the sum of stroke Indices was calculated for evaluating the overall morbidity during a particular period of reperfusion. Mortality was observed for 24 hours after dip removal. Although, depending on the tuning of the drug administration, the low-dose (0.01 mg/kg) nimodipine worsened the morbidity in the gerbils with 10-mln ischemia, the high-dose (0.1 mg/kg) of the drug had a dear beneficial effect on the mortality associated with cerebral ischemia. These results are considered worthwhile for further trials to assess the usefulness of nimodipine as a therapeutic agent In the management of the acute iscbemk stroke. Stroke Vol 17, No 4, 1986 RECENTLY there has been increasing interest in the pathophysiological role of calcium in ischemic brain injury.1 "* Calcium has been implicated in the final common pathway not only for contraction of vascular smooth muscle in a variety of pathophysiological conditions, 5 but also for cell death caused by membrane degradation. 6 ' 7 It seems justified, therefore, to consider whether calcium entry blockers may have therapeutic effects on ischemic brain injury.Amongst several calcium antagonists, nimodipine [BAY e 9736, isopropyl (2-methoxyethyl)-l,4-dihydro-2,6-dimethyl-4(3-nitrophenyl)-3,5-pyridinedi-carboxylate] has been shown to be one of the most promising ones with a preferential action on cerebral blood vessels. -9 Kazda et al 10 suggested that nimodipine prevents the postischemic impairment of reperfusion following 7-min global cerebral ischemia in cats, and Hoffmeister et al" showed in the same model, that the circulatory effects are paralleled by improvement of functional recovery with increased survival rates. Following these studies, several investigations 12 "16 were reported on the pathophysiological effects of this drug on cerebral ischemia.The mongolian gerbil (Meriones unguiculatus), which lacks a functional connection between the carotid and vertebrobasilar arterial circulations, 17 -18 has great advantages for the screening of compounds as protective agents against brain ischemia. "23 There have been, however, no reports on the effects of nimodipine on the gerbil model of cerebral ischemia. In the present study, by assessing the changes both in morbidity and mortality following temporary bilateral Received March 20, 1985; revision # 2 accepted October 9, 1985. common carotid occlusion in gerbils with nimodipine or vehicle treatment, we attempted to evaluate the therapeutic potency of the drug in the acute phase of ischemic stroke.Methods A total of 202 adult Mongolian gerbils of both sexes we...

Prevention of Postischemic Hyperthermia Prevents Ischemic Injury of CA1 Neurons in Gerbils

“…In the past most laboratories studying neuropro tection of selective vulnerability in the gerbil have tried to exclude temperature effects by preventing a drop of temperature below control values (Hall mayer et aI., 1985;Fujisawa et al, 1986;Kirino et al, 1986;Gill et al, 1988;Imaizumi and Kogure, 1988;Mar coux et al, 1988;Buchan and Pulsinelli, 1989). The present findings demonstrate that this does not ex clude a temperature dependence because neuropro tection may have been mediated by preventing postischemic hyperthermia.…”

Neuroprotective Effects by Nimodipine Treatment in the Experimental Global Ischemic Rat Model : Real Time Estimation of Glutamate

“…In contrast, Lazarewicz et al 26) proposed that nimodipine could directly protect neurons in the rabbit brain by intracellular Ca 2+ antagonism rather than by inhibition of Ca 2+ influx. Despite many reports that Ca 2+ channel blockade induces a cascade reaction, the action of nimodipine on presynaptic glutamate release remains poorly understood 14,16,18,25) . Under clinical circumstances, surgeons occasionally encounter ischemic conditions, such as multiple temporary clipping during aneurysm surgery or vascular clamping during carotid endarterectomy and bypass surgery.…”

The Effect of Nimodipine on High-Energy Phosphates and Intracellular pH During Cerebral Ischemia

“…Times indicate minutes following bilateral common carotid artery (CCA) ligation. extensively studied (Bunnell et al, 1987;Cohen and Mayevsky, 1989;Fujisawa et al, 1986;Heffez and Passonneau, 1985; Mossakowski and Gadamski, 1987).…”