Effective reduction of infarct volume by gap junction blockade in a rodent model of stroke

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✓ Several lines of evidence indicate that the extent of ischemic injury is not defined immediately after arterial occlusion, but that infarction expands over time. Episodes of spreading depression have been linked to this secondary increase in infarct volume. Tissue bordering the infarction fails to repolarize following spreading depression and is incorporated into the lesion. The result is that ischemic infarctions expand stepwise after each episode of spreading depression. Another line of evidence has demonstrated that gap junction blockers effectively inhibit spreading depression.

These observations suggest that traffic of potentially harmful cytosolic messengers between ischemic cells and surrounding nonischemic cells might cause amplification of injury in focal stroke. It is therefore conceivable that minimizing gap junction permeability might reduce final infarct volume. To test this hypothesis, the authors pretreated rats with the gap junction blocker, octanol, before occluding the middle cerebral artery and compared the sizes of the ischemic lesions to those in rats that received the vehicle, dimethyl sulfoxide, prior to arterial occlusion. Histopathological analysis was performed 24 hours later. The 12 octanol-treated animals showed a significantly decreased mean infarction volume (80 ± 16 mm3) compared with the nine control rats (148 ± 9 mm3). In a separate set of experiments, the frequency of experimentally induced waves of spreading depression was evaluated after octanol treatment. Octanol pretreatment resulted in complete inhibition in two of nine animals, transient inhibition in five, and no inhibition in two.

The results indicate that gap junction inhibitors, when not limited by toxicity, have significant therapeutic potential in the treatment of acute stroke.

Article Information

Address reprint requests to: Maiken Nedergaard, M.D., Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595.

© AANS, except where prohibited by US copyright law.

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Figures

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    Histogram depicting infarct volume 24 hours after occlusion of the MCA in nine control and 12 octanol-treated rats. Octanol treatment reduced infarct volume by 60% (p < 0.01). Analysis of variance was used to compare the means across the two groups, and Scheffé's F test was used to determine the significance level.

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    Diagram illustrating the distribution of infarction 24 hours after occlusion of the MCA in individual animals. Infarction was restricted to the lateral parts of the striatum, with no animal showing expansion into the ventral striatum. In contrast, the size and extent of the cortical lesion varied from animal to animal and the cortical lesions were generally larger in the control group. Cortical infarction was evident in all nine rats in the control group, whereas only five of 12 rats developed significant cortical lesions in the octanol-treated group.

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    Representative echocardiography demonstrating that spreading depression in the neocortex is inhibited by octanol. A: Repeated waves of spreading depression are evoked by injection of KCl (small arrows). Injection of KCl fails to evoke spreading depression 30 minutes after octanol treatment. Doubling the dose of KCl did not result in generation of spreading depression; however, spreading depression could be regenerated approximately 60 minutes after octanol administration. Normal-appearing waves were evoked during the remaining observation period. B: Recording from one representative animal in which generation of waves of spreading depression was not regained after treatment with octanol; its heart stopped 110 minutes after octanol administration. Anoxic depolarization was not affected by octanol treatment in either of the animals.

References

  • 1.

    Charles ACNaus CCZhu Det al: Intercellular calcium signaling via gap junctions in glioma cells. J Cell Biol 118:1952011992Charles AC Naus CC Zhu D et al: Intercellular calcium signaling via gap junctions in glioma cells. J Cell Biol 118:195–201 1992

    • Search Google Scholar
    • Export Citation
  • 2.

    Cornell-Bell AHFinkbeiner SMCooper MSet al: Glutamate induces calcium waves in cultured astrocytes: long range glial signaling. Science 247:4704731990Cornell-Bell AH Finkbeiner SM Cooper MS et al: Glutamate induces calcium waves in cultured astrocytes: long range glial signaling. Science 247:470–473 1990

    • Search Google Scholar
    • Export Citation
  • 3.

    Dermietzel RSpray DC: Gap junctions in the brain: where, what type, how many and why? TINS 16:1861921993Dermietzel R Spray DC: Gap junctions in the brain: where what type how many and why? TINS 16:186–192 1993

    • Search Google Scholar
    • Export Citation
  • 4.

    Finkbeiner S: Calcium waves in astrocytes—filling in the gaps. Neuron 8:110111081992Finkbeiner S: Calcium waves in astrocytes—filling in the gaps. Neuron 8:1101–1108 1992

    • Search Google Scholar
    • Export Citation
  • 5.

    Ginsberg M: Neuroprotection in brain ischemia: an update. The Neuroscientist 1:951031995Ginsberg M: Neuroprotection in brain ischemia: an update. The Neuroscientist 1:95–103 1995

    • Search Google Scholar
    • Export Citation
  • 6.

    Grafstein B: Mechanism of spreading cortical depression. J Neurophysiol 19:1541711956Grafstein B: Mechanism of spreading cortical depression. J Neurophysiol 19:154–171 1956

    • Search Google Scholar
    • Export Citation
  • 7.

    Hansen AJ: Effect of anoxia on ion distribution in the brain. Physiol Rev 65:1011481985Hansen AJ: Effect of anoxia on ion distribution in the brain. Physiol Rev 65:101–148 1985

    • Search Google Scholar
    • Export Citation
  • 8.

    Hossmann KA: Excitotoxic Mechanisms and Focal Ischemia. Philadelphia: Lippincott-Raven1996Hossmann KA: Excitotoxic Mechanisms and Focal Ischemia. Philadelphia: Lippincott-Raven 1996

    • Search Google Scholar
    • Export Citation
  • 9.

    Hossmann KA: Viability thresholds and the penumbra of focal ischemia. Ann Neurol 36:5575651994Hossmann KA: Viability thresholds and the penumbra of focal ischemia. Ann Neurol 36:557–565 1994

    • Search Google Scholar
    • Export Citation
  • 10.

    Iijima TMies GHossmann KA: Repeated negative DC deflections in rat cortex following middle cerebral artery occlusion are abolished by MK-801: effect on volume of ischemic injury. J Cereb Blood Flow Metab 12:7277331992Iijima T Mies G Hossmann KA: Repeated negative DC deflections in rat cortex following middle cerebral artery occlusion are abolished by MK-801: effect on volume of ischemic injury. J Cereb Blood Flow Metab 12:727–733 1992

    • Search Google Scholar
    • Export Citation
  • 11.

    Lauritzen MHansen AJ: The effect of glutamate receptor blockade on anoxic depolarization and cortical spreading depression. J Cereb Blood Flow Metab 12:2232291992Lauritzen M Hansen AJ: The effect of glutamate receptor blockade on anoxic depolarization and cortical spreading depression. J Cereb Blood Flow Metab 12:223–229 1992

    • Search Google Scholar
    • Export Citation
  • 12.

    Mesnil MPiccoli CTiraby Get al: Bystander killing of cancer cells by herpes simplex virus thymidine kinase gene is mediated by connexins. Proc Natl Acad Sci USA 93:183118351996Mesnil M Piccoli C Tiraby G et al: Bystander killing of cancer cells by herpes simplex virus thymidine kinase gene is mediated by connexins. Proc Natl Acad Sci USA 93:1831–1835 1996

    • Search Google Scholar
    • Export Citation
  • 13.

    Mies GIijima THossmann KA: Correlation between periinfarct DC shifts and ischaemic neuronal damage in rat. Neuroreport 4:7097111993Mies G Iijima T Hossmann KA: Correlation between periinfarct DC shifts and ischaemic neuronal damage in rat. Neuroreport 4:709–711 1993

    • Search Google Scholar
    • Export Citation
  • 14.

    Nedergaard M: Direct signaling from astrocytes to neurons in cultures of mammalian brain cells. Science 263:176817711994Nedergaard M: Direct signaling from astrocytes to neurons in cultures of mammalian brain cells. Science 263:1768–1771 1994

    • Search Google Scholar
    • Export Citation
  • 15.

    Nedergaard MAstrup J: Infarct rim: effects of hyperglycemia on direct current potential and [14C]2-deoxyglucose phosphorylation. J Cereb Blood Flow Metab 6:6076151986Nedergaard M Astrup J: Infarct rim: effects of hyperglycemia on direct current potential and [14C]2-deoxyglucose phosphorylation. J Cereb Blood Flow Metab 6:607–615 1986

    • Search Google Scholar
    • Export Citation
  • 16.

    Nedergaard MCooper AJGoldman SA: Gap junctions are required for the propagation of spreading depression. J Neurobiol 28:4334441995Nedergaard M Cooper AJ Goldman SA: Gap junctions are required for the propagation of spreading depression. J Neurobiol 28:433–444 1995

    • Search Google Scholar
    • Export Citation
  • 17.

    Nedergaard MGoldman S: Spreading depression—a gap junction mediated event? in Spray RDermietzel DC (eds): Gap Junctions in the Nervous System. Austin: R Landes1996Nedergaard M Goldman S: Spreading depression—a gap junction mediated event? in Spray R Dermietzel DC (eds): Gap Junctions in the Nervous System. Austin: R Landes 1996

    • Search Google Scholar
    • Export Citation
  • 18.

    Nedergaard MHansen AJ: Characterization of cortical depolarizations evoked in focal cerebral ischemia. J Cereb Blood Flow Metab 13:5685741993Nedergaard M Hansen AJ: Characterization of cortical depolarizations evoked in focal cerebral ischemia. J Cereb Blood Flow Metab 13:568–574 1993

    • Search Google Scholar
    • Export Citation
  • 19.

    Nicholson CKraig RP: The behavior of extracellular ions during spreading depression in Zeuthen T (ed): The Application of Ion-Selective Microelectrodes. Amsterdam: Elsevier1981Nicholson C Kraig RP: The behavior of extracellular ions during spreading depression in Zeuthen T (ed): The Application of Ion-Selective Microelectrodes. Amsterdam: Elsevier 1981

    • Search Google Scholar
    • Export Citation
  • 20.

    Parpura VBasarsky TALiu F: Glutamate-mediated astrocyteneuron signalling. Nature 369:7447471994Parpura V Basarsky TA Liu F: Glutamate-mediated astrocyteneuron signalling. Nature 369:744–747 1994

    • Search Google Scholar
    • Export Citation
  • 21.

    Siesjo B: Pathophysiology and treatment of focal cerebral ischemia. I. Pathophysiology. J Neurosurg 77:1691841992Siesjo B: Pathophysiology and treatment of focal cerebral ischemia. I. Pathophysiology. J Neurosurg 77:169–184 1992

    • Search Google Scholar
    • Export Citation
  • 22.

    Siesjo BKZhao QPahlmark Ket al: Glutamate, calcium, and free radicals as mediators of ischemic brain damage. Ann Thorac Surg 59:131613201995Siesjo BK Zhao Q Pahlmark K et al: Glutamate calcium and free radicals as mediators of ischemic brain damage. Ann Thorac Surg 59:1316–1320 1995

    • Search Google Scholar
    • Export Citation
  • 23.

    Smith SJ: Neural signalling. Neuromodulatory astrocytes. Curr Biol 4:8078101994Smith SJ: Neural signalling. Neuromodulatory astrocytes. Curr Biol 4:807–810 1994

    • Search Google Scholar
    • Export Citation
  • 24.

    Tamura AGraham DIMcCulloch Jet al: Focal cererbral ischaemia in the rat: 1. Description of technique and early neuropathological consequences following middle cerebral artery occlusion. J Cereb Blood Flow Metab 1:53601981Tamura A Graham DI McCulloch J et al: Focal cererbral ischaemia in the rat: 1. Description of technique and early neuropathological consequences following middle cerebral artery occlusion. J Cereb Blood Flow Metab 1:53–60 1981

    • Search Google Scholar
    • Export Citation

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