Oxidative metabolism during recurrent seizures in the penicillin treated hippocampus

Lewis, Darrell V.; O’Connor, Michael J.; Schuette, William H.

doi:10.1016/0013-4694(74)90184-9

Cited by 32 publications

(8 citation statements)

References 20 publications

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“…The fractional changes in fluorescence (AFIF) from the potential-sensitive styryl dye after bicuculline were about 5 x 10-3. These fractional changes are 1 or 2 orders of magnitude smaller than the fractional changes in NADH fluorescence that accompany interictal epileptiform discharges (Lewis et al, 1974;Schuette et al, 1974) and ictal seizures (Jobsis et al, 1971;O'Connor et al, 1972;Lewis et al, 1974;Evans and Smith, 1987). Our signals (with a styryl dye) were also 2 orders of magnitude smaller than the signals found by Evans and Smith (1987) with an oxonol dye.…”

Section: Discussionmentioning

confidence: 45%

“…The signals presented in this paper were measured with a time resolution of less than 5 msec; more than 2 orders of magnitude faster than the measurements of NADH and oxonol fluorescence (Jobsis et al, 197 1; O'Connor et al, 1972; Lewis et al, 1974;Schuette et al, 1974;Evans and Smith, 1987). Since the inter----V--- Figure 8.…”

Section: Discussionmentioning

confidence: 86%

“…Early attempts to use multisite imaging to measure epileptic activity in cortex (Schuette et al, 1974) involved measurements of NADH fluorescence, an indicator of the intracellular metabolic state. Optical measurements during epileptic events from single sites in cortex have been reported by several laboratories (Jobsis et al, 197 1;Rosenthal and Jobsis, 1971;O'Connor et al, 1972;Lewis et al, 1974;Evans and Smith, 1987). While NADH fluorescence was measured in most of these experiments, Evans and Smith (1987) also measured the fluorescence of a potential-sensitive oxonol dye.…”

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confidence: 97%

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Optical recordings of the cortical response to whisker stimulation before and after the addition of an epileptogenic agent

London

Cohen

1989

J. Neurosci.

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Optical recording methods using voltage-sensitive dyes were used to monitor activity in rat somatosensory cortex. We measured evoked signals in response to whisker stimulation before (control) and after the addition of the epileptogenic agent, bicuculline, and also detected spontaneous interictal events that occurred after bicuculline. Bicuculline led to an increase in the size, duration, cortical extent, and, surprisingly, the latency of the evoked responses. These enhanced evoked responses appeared to originate in the region of the control response and propagate outward. In contrast, the spontaneous signals appeared to originate at random cortical positions and had a more variable cortical extent. A transition signal measured just after the addition of bicuculline was larger than the control response but localized and rapid in time course. In most cases, there was a good correlation between the optical recordings and field potential measurements made with a ball electrode on the cortical surface, but there were occasional instances where the optical signal disappeared while the ball electrode signal was unchanged.

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Section: Discussionmentioning

confidence: 45%

Section: Discussionmentioning

confidence: 86%

mentioning

confidence: 97%

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Optical recordings of the cortical response to whisker stimulation before and after the addition of an epileptogenic agent

London

Cohen

1989

J. Neurosci.

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“…Numerous reports confirmed that neuronal excitation in intact brain was accompanied by sustained oxidation of NADH [19,30,[34][35][36][37][38][39][40][41][42][43][44][45]. A close correlation was also observed between NADH oxidation and oxygen consumption in cat and rat neocortex [46,47].…”

Section: Redox Responses In Excited Brain Tissue In Vivomentioning

confidence: 78%

Differences in O2 availability resolve the apparent discrepancies in metabolic intrinsic optical signals in vivo and in vitro

Turner

Foster

Galeffi

et al. 2007

Trends in Neurosciences

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Monitoring changes in the fluorescence of metabolic chromophores, reduced nicotinamide adenine dinucleotide and flavin adenine dinucleotide, and the absorption of cytochromes, is useful to study neuronal activation and mitochondrial metabolism in the brain. However, these optical signals evokedby stimulation, seizures and spreading depression in intact brain differ from those observed in vitro. The responses in vivo consist of a persistent oxidized state during neuronal activity followed by mild reduction during recovery. In vitro, however, brief oxidation is followed by prolonged and heightened reduction, even during persistent neuronal activation. In normally perfused, oxygenated and activated brain tissue in vivo, partial pressure of oxygen (P O2 ) levels often undergo a brief 'dip' that is always followed by an overshoot above baseline, due to increased blood flow (neuronal-vascular coupling). By contrast, in the absence of blood circulation, tissue P O2 in vitro decreases more markedly and recovers slowly to baseline without overshooting. Although oxygen is abundant in vivo, it is diffusion-limited in vitro. The disparities in mitochondrial and tissue oxygen availability account for the different redox responses. Changes in redox level of mitochondrial respiratory chain components can be monitored in live brain tissue by optical imagingChanges in fluorescence of metabolic cofactors [i.e. reduced nicotinamide adenine dinucleotide (NADH) ‡ and flavin adenine dinucleotide (FAD)] involved in energy processes, and in the absorption spectrum of cytochromes, provide a measure of their redox level. Mitochondrial energy metabolism is tightly coupled with neuronal activity, and changes in metabolic activity alter the redox level of these cofactors. Optical changes related to redox state have been used for many years to gauge the metabolic activity in brain and in other organs. Relating redox responses to electrical, mechanical or secretory processes has provided a rich source of data on the coupling of metabolic activity to their function. Such investigations in mammalian brain shed light on the mechanism of seizures, of spreading depression (SD) and of hypoxia and ischemia. Recently, however, a discrepancy has become apparent between the pattern of redox changes in intact, perfused brain 'in vivo' * , and isolated preparations of central neurons, tissue slices and slice cultures maintained 'in vitro' † in an organ bath. This essay aims at resolving the apparent discrepancy.Corresponding author: Turner, D.A. (dennis.turner@duke.edu). ‡ The term 'reduction' is used to denote shifts in redox state away from oxidation, not a decrease in a variable. * To avoid ambiguity, we use 'in vivo' to mean brain tissue in its anatomical location (in situ) and perfused by blood, usually studied in an anesthetized animal with functioning lungs, heart and autonomic reflexes. † 'In vitro' means isolated cells, tissue slices, cell cultures and organotypic slice cultures maintained in an oxygenated, saline-perfused organ bath. NI...

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“…A seizure is usually felt to be an active process involving excitatory neurons. Studies of focal epilepsy suggest that there is increased neuronal activity, manifested by increased blood flow and hypermetabolism, during seizures (Ingvar, 1973;Lewis et al, 1974;Kuhl et al, 1980). The result is usually excess activity, such as clonic motor movements, in the neuronal system involved (Russell and Whitty, 1953).…”

Section: Discussionmentioning

confidence: 99%

Ictal Blindness and Status Epilepticus Amauroticus

et al. 1985

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Five cases of ictal blindness are presented. All are documented to be ictal by simultaneous EEG monitoring during the period of blindness. In three cases, the blindness was complete; in two, it manifested as a homonymous hemianopia. Three cases (including the two with hemianopia) were secondary to vascular lesions; one case was due to a metastatic lesion; and there was one case of idiopathic epilepsy. Age ranged from 13 to 74 years. In all cases, the blindness was reversible with anticonvulsant therapy. All cases but one lasted from hours to days, meeting a criterion of "status epilepticus amauroticus." In the literature, ictal blindness is seldom reported and even less often documented. Unexplained cortical blindness might represent unrecognized seizure activity more often than is appreciated.

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Oxidative metabolism during recurrent seizures in the penicillin treated hippocampus

Cited by 32 publications

References 20 publications

Optical recordings of the cortical response to whisker stimulation before and after the addition of an epileptogenic agent

Optical recordings of the cortical response to whisker stimulation before and after the addition of an epileptogenic agent

Differences in O2 availability resolve the apparent discrepancies in metabolic intrinsic optical signals in vivo and in vitro

Ictal Blindness and Status Epilepticus Amauroticus

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