Localization of Carbonic Anhydrase in the Cerebrum and Cerebellum of Normal and Audiogenic Seizure Mice

Anderson, Richard E.; Engstrom, Fae L.; Woodbury, Dixon M.

doi:10.1111/j.1749-6632.1984.tb12378.x

Cited by 27 publications

(16 citation statements)

References 5 publications

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“…Using several approaches, CA II has been shown by other workers to be localized primarily in glial tissue and, like pyruvate carboxylase [13], is not found in most neurons [5,35,36]. Anderson et al [42] showed that CA II is present in both glial astrocytes and oligodendro cytes. If CA IV, CA V or CA III are present they were below detection limits in the cells used in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Anderson et al [42] found intramitochondrial CA II immunoreactivity, which could be a cross-reaction with CA V, in cultured neonatal oligodendrocytes but not in astrocytes. Similarly, we did not detect CA-V immunore activity in cultured neonatal astrocytes ( fig.…”

Section: Discussionmentioning

confidence: 99%

“…Longmuir et al [47] showed that CA could increase the rate of diffusion of bicarbonate/CO, through solutions. Furthermore, much of the CA II in the brain is tightly associated with the inner leaflet of the plasma membrane and outer leaflets of organelle membranes [42,48]. It may there fore be involved in transmembrane CO,/bicarbonate transport.…”

Section: Discussionmentioning

confidence: 99%

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Effect of Carbonic Anhydrase Inhibition and Acetoacetate on Anaplerotic Pyruvate Carboxylase Activity in Cultured Rat Astrocytes

et al. 1997

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In peripheral tissues, carbonic anhydrase (CA) inhibition secondarily decreases the anaplerotic activity of pyruvate carboxylase activity leading to a decline in citric acid cycle intermediates and glutamate. In view of the important role of pyruvate carboxylase in the brain, we examined the effects of CA inhibition on pyruvate-carboxylase-mediated [¹⁴C]CO₂ fixation in cultured astrocytes from postnatal rat brains. Incubation with H[¹⁴C]O3̄ led to radiolabeling of metabolites found both in the cells and in the medium. These were separated by ion exchange chromatography for identification. Ethoxyzolamide (ETZ), a sulfonamide CA inhibitor (SCAT) with a heterocyclic side group, caused a 43–73% decrease in cell lysate [α-ketoglutarate] and ¹⁴C incorporation into major products of pyruvate carboxylation in the cell lysates and cell medium (i.e., released products). Half-maximal inhibition of [¹⁴C]CO₂ fixation was observed between 1 and 3 x l0^–7M. This is similar to the IC₅₀ value for ETZ inhibition of events in other cells that are thought to be mediated by CA. Inhibition was also observed with trifluor-methanesulfonamide, an aliphatic SCAI, providing further evidence that this effect is mediated by CA. Western blot analysis using isozyme-specific anti-sera indicated that astrocytes contain CA II, a cytosolic isozyme, but CA in, CA IV and CA V could not be detected. This finding is unusual since the effects of SCAIs on pyruvate carboxylation in other tissues have been attributed to inhibition of the intramitochondrial isozyme, CA V. [¹⁴C]CO₂ fixation was also decreased by lowering media [pyruvate] or by addition of 5 mM acetoacetate. It is hypothesized that SCAIs may inhibit pyruvate carboxylation in astrocytes by limiting the supply of bicarbonate to this enzyme while ketone bodies, by inhibiting glucose oxidation, may limit the supply of pyruvate. Interestingly, both SCAIs and ketogenic diets are used to treat adolescent forms of epilepsy. The possibility that these treatments might ultimately work by affecting anaplerotic pyruvate carboxylase activity in the brain is discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effect of Carbonic Anhydrase Inhibition and Acetoacetate on Anaplerotic Pyruvate Carboxylase Activity in Cultured Rat Astrocytes

et al. 1997

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“…Disappointingly, the anticonvulsant sulfonamide drugs did not provide effective long term therapy for epileptic patients. Indeed, Anderson et al [31] showed that the synthesis of CA II in brain is upregulated after multiple doses of acetazolamide. Recently, Halmi et al [15] described that the expression of CA II is also induced in the CA1 cells after 3-12h of exposure to kainic acid for inducing status epilepticus.…”

Section: Ca and Seizures: Several Hypothetical Mechanismsmentioning

confidence: 98%

“…Various physiological roles are attributed to mammalian CAs in the brain such as fluid and ion compartmentation [30], formation of cerebrospinal fluid [12], regulation of its pH and ionic constituents [12], seizure activity [31], regulation of GABAergic signalling [24,25], respiratory response to carbon dioxide [32], generating bicarbonate for biosynthetic reactions [33], proliferation and differentiation [21].…”

Section: Roles Of Ca Isozymes In the Cnsmentioning

confidence: 99%

Carbonic Anhydrase Inhibitors as Anticonvulsant Agents

Thiry

Dogné²,

Supuran³

et al. 2007

CTMC

207

142

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Seizures are one of the most common neurological disorders in clinical medicine. Triggering mechanisms by which seizures form remain unclear, but are related to a rapid change in ionic composition, including an increase of intracellular potassium concentration and pH shifts within the brain. pH buffering of extra- and intracellular spaces is mainly carried out by the CO(2)/ HCO(3)(-) buffer, the equilibration of the two species being assured by the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). Some carbonic anhydrase inhibitors (CAIs) are used as anticonvulsants in the treatment of epilepsy. In this review, we will describe the link between CA and seizures on the basis of several putative mechanisms. Several CA isozymes have been pointed out for their contribution to epileptiform activity. An overview of the CA isozyme expression in the brain and of their specifics roles is also discussed. This article reviews the research achievements published on CA inhibitors, clinically used as anticonvulsant and those under development.

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