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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

AvaliaÃÃo de eficÃcia e seguranÃa da acetazolamida na doenÃa periodontal experimental. / Efficacy and safety assessment of acetazolamide in experimental periodontal disease.

Tercio Carneiro Ramos 30 June 2010 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / As doenÃas periodontais sÃo as principais causas de perda de dentes em adultos. O fator etiolÃgico preponderante para desencadear a periodontite à o acumulo do biofilme dental com predominÃncia de bactÃrias anaerÃbicas gram negativas. Apesar de ser de origem bacteriana a resposta inflamatÃria induzida a partir de fatores do hospedeiro pode influenciar na progressÃo e nas caracterÃsticas clÃnicas da doenÃa periodontal. A perda Ãssea alveolar à tÃpica na evoluÃÃo desta patologia e dependente da atividade osteoclÃstica. Por sua vez, um dos mecanismos de reabsorÃÃo Ãssea por estas cÃlulas à atravÃs da produÃÃo de prÃtons liberados nos vacÃolos de reabsorÃÃo pela atividade da anidrase carbÃnica. Tem sido relatado que inibidores desta enzima, como acetazolamida, tem aÃÃo supressora sobre osteoclastos. O objetivo deste estudo foi analisar o efeito da acetazolamida (ACTZ) na perda Ãssea induzida no modelo de periodontite experimental em ratos, bem como a dosagem de biomarcadores sÃricos do processo inflamatÃrio periodontal e anÃlise histolÃgica do periodonto. AnÃlises de seguranÃa tambÃm foram realizadas atravÃs de hemograma completo, dosagens de TGP, TGO, gama-GT e histopatologia de ÃrgÃos como: fÃgado, rins, baÃo, coraÃÃo e pulmÃo. Para avaliaÃÃo da perda Ãssea alveolar 50 ratos receberam ligaduras de nylon na regiÃo do segundo molar superior esquerdo. Os animais foram divididos em seis grupos: Grupo veÃculo (propilenoglicol) (n=9), grupo controle positivo (alendronato 0,08 mg/Kg) (n=7), grupo controle negativo (salina) (n=9) e grupos que receberam acetazolamida via I.P. nas doses (8,3, 25 e 75 mg/Kg [grupos ACTZ8,3, ACTZ25 e ACTZ75, respectivamente] n= 7, 9 e 9). ApÃs 11 dias, os ratos foram mortos. A perda Ãssea alveolar foi avaliada macroscopicamente atravÃs da Ãrea de exposiÃÃo de raiz. Em outros quatro grupos, ACTZ25 (n=5) e veÃculo (n=5), o periodonto foi analisado histologicamente apÃs 11 e 17 dias de ligadura por coloraÃÃo em HE. Biomarcadores sÃricos foram dosados (IL-1&#61537;, IL-4, fractalkine, CINC-2, CINC-3, LIX, GM-CSF, &#946;NGF, VEGF e CNTF) atravÃs da tÃcnica de microarray antes e depois da ligadura em trÃs grupos; ACTZ25, Veiculo e Sham (cirurgia simulada). No grupo de ACTZ25 foi realizada a anÃlise de seguranÃa (alpha=5%). Macroscopicamente, o grupo alendronato (controle positivo) apresentou a menor perda Ãssea, seguido do grupo ACTZ75 e ACTZ25 (p<0.05) quando comparados aos controles veÃculo e salina que nÃo diferiram entre si (p>0.05). Histologicamente, o grupo ACTZ apresentou a menor reabsorÃÃo de osso e cemento (p<0,05) apÃs 17 dias de ligadura, nÃo houve diferenÃa entre o grupo ACTZ25 e o veÃculo quanto ao infiltrado inflamatÃrio (P>0,05) . As maiores concentraÃÃes de IL-4 e CNTF foram observadas no grupo ACTZ25 (p< 0,05) quando comparado ao grupo veÃculo. As anÃlises de seguranÃa demonstraram que acetazolamida na dosagem de 25 mg/Kg foi bem tolerada sem alteraÃÃes significativas do hemograma, nas enzimas hepÃticas e histopatologia dos ÃrgÃos pesquisados. ConcluÃmos que a acetazolamida pode proteger o periodonto da reabsorÃÃo Ãssea induzida por ligadura em ratos e pode estar associada a mediadores envolvidos com o reparo, como a IL-4 e CNTF, alÃm de ser bem tolerada. / Periodontal diseases are the main cause of tooth loss in adults. The preponderant etiologic factor for the onset of periodontitis is the accumulation of dental biofilm with predominance of anaerobic gram negative bacteria. In spite of being of bacterial origin, the inflammatory response induced by factors in the host may influence the progression and clinical characteristics of periodontal disease. Alveolar bone is typical in the development of this pathology and is dependent on osteoclastic activity. In turn, one of the mechanisms of bone resorption by these cells is through the production of protons released in the resorption vacuoles by carbonic anhydrase activity. It has been reported that carbonic anhydrase inhibitors, such as acetazolamide, have a suppressive action on osteoclasts. The aim of this study was to analyze the effect of acetazolamide (ACTZ) on bone loss induced in the experimental periodontitis model in rats, as well as the dosage of seric biomarkers in the periodontal inflammatory process and histologic analysis of the periodontium. Safety analyses were also performed by means of a complete hemogram, biochemical tests for TGP, TGO, gama-GT and histopathology of organs such as: the liver, kidneys, spleen, heart and lungs. To evaluate alveolar bone loss, 50 rats received nylon ligatures in the maxillary left second molar region. The animals were divided into six groups: Vehicle Group (propylenoglycol) (n=9), Positive Control Group (alendronate 0.08 V (n=7), Negative Control Group (saline) (n=6) and Groups that received acetazolamide I.P. in the following doses: (8.3, 25 and 75 mg/Kg [Groups ACTZ8,3, ACTZ25 and ACTZ75 respectively] n= 7, 9 and 9). After 11 days, the rats were sacrificed. Alveolar bone loss was macroscopically evaluated by means of the area of root exposure. In another four groups, ACTZ25 (n=5) and vehicle (n=5), the periodontium was histologically analyzed after 11 and 17 days of ligature, by HE staining. Seric biomarkers were dosed (IL-1&#61537;, IL-4, fractalkine, CINC-2, CINC-3, LIX, GM-CSF, &#946;NGF, VEGF and CNTF) by means of the microarray technique before and after ligature in three groups; ACTZ25, Vehicle and Sham (simulated surgery). In the ACTZ25 group, safety analysis was performed (alpha=5%). Macroscopically, the alendronate Group (positive control) presented the lowest bone loss, followed by Groups ACTZ75 and ACTZ25 (p<0.05) when compared with the vehicle and saline controls, which did not differ between them (p>0.05). Histologically, the ACTZ group presented the lowest bone and cement resorption (p<0.05) after 17 days of ligature, and there was no difference between the ACTZ25 and vehicle groups with regard to inflammatory infiltrate (P>0.05). The highest concentrations of IL-4 and CNTF were observed in Group ACTZ25 (p< 0.05) when compared with the vehicle group. The safety analyses demonstrated that acetazolamide at the dose of 25 mg/Kg was well tolerated without significant alterations in the hemogram, hepatic enzymes and histopathology of the researched organ. It was concluded that acetazolamide may protect the periodontium from bone resorption induced by ligature in rats, and may be associated with mediators involved in repair, such as IL-4 and CNTF, in addition to being well tolerated.
2

Hemorrhagic Anuria With Acute Kidney Injury After a Single Dose of Acetazolamide: A Case Study of a Rare Side Effect

Lawson, Christy M., Morris, Leisa, Wilson, Vera, Burns, Bracken 29 August 2020 (has links)
Acetazolamide (ACZ) is a relatively commonly used medication in critical illness, glaucoma and altitude sickness. ACZ is sometimes used in the intensive care unit to assist with the treatment of metabolic alkalosis in ventilated patients. This is a case report of a patient who received two doses of ACZ, one week apart, for metabolic alkalosis and subsequently developed renal colic and dysuria that progressed to hemorrhagic anuria and acute kidney injury. This is an incredibly rare side effect of ACZ therapy, and has been reported in a few case reports in the literature, but usually is associated with a longer duration of therapy. This case resolved entirely within 24 hours with aggressive fluid therapy. Clinicians using ACZ therapy for any reason should be aware of this rare but significant side effect.
3

Quantification of the potentiating effects of caffeine on the teratogenicity of acetazolamide in C57BL/6J mice

Kelich, Stephanie L. January 1988 (has links)
The study was designed to determine what type of potentiation,.if any, occurred between caffeine and acetazolamide. Caffeine (75 mg/kg) and/or acetazolamide (200, 1000, or 1500 mg/kg) were administered to pregnant C57BL/6J dams on day 9 of gestation. Fetuses were removed on the eighteenth day of gestation via cesarean section and examined for gross morphological malformations using a Bausch & Lomb SKV1070P dissecting microscope. Treatment with HD-ACZM and HD+CAFF resulted in a reduction of fetal weight. Maternal exposure to MD-ACZM and HD-ACZM caused a statistically significant (P < .001) and dose-dependent increase in the percent of C57BL/6J fetuses with ectrodactyly along with increased severity of the defects displayed (relative to controls). An increase in the number of ectrodactylous fetuses and the severity of defects was also observed in all groups administered caffeine and acetazolamide, reaching statistical significance in the MD+CAFF and HD+CAFF groups (P < .001). Because potentiation of the teratogenic effects of acetazolamide was exhibited only in the MD+CAFF vs. MD-ACZM groups, the type of potentiation occurring between caffeine and acetazolamide can not be determined. / Department of Physiology and Health Science
4

Potentiating effects of caffeine on the teratogenicity of acetazolamide in two strains of mice

Urbano, Charissa M. January 1988 (has links)
This study was designed to determine the effect of caffeine on the teratogenicity of acetazolamide in susceptible and resistant strains of inbred mice. The highly susceptible C57BL/6J and more resistant SWV strain were used. Pregnant C57BL/6J and SWV mice were treated with caffeine, low or high dose acetazolamide, or a combination of both agents during the sensitive period of development. Untreated and vehicle-treated groups served as controls. Individual fetuses were examined for gross morphological abnormalities and skeletal variations.Findings1. A highly significant (P<.001) increase in fetal malformations, especially right forelimb ectrodactyly, was evident in C57BL/6J litters exposed on day 9 of gestation to both agents when contrasted with those exposed to either agent alone. Both frequency and severity of ectrodactyly was potentiated by caffeine.2. The SWV strain was resistant to the interaction of caffeine and acetazolamide when treated on day 9 of gestation. However, a highly significant (P<.001) increase in the rate of fetal malformation was found in litters whose dams were treated with high dose acetazolamide and caffeine on day 8 of gestation. The most common malformations observed were exencephaly and umbilical hernia.3. No differences in maternal mortality, fetal weight, litter size, or embryo mortality could be attributed to treatment in either strain.4. Skeletal examination of the number of ossified cervical and caudal vertebral centra revealed a reduction in ossification among C57BL/6J litters exposed to high dose acetazolamide or acetazolamide plus caffeine. These same centers of ossification were mildly affected by treatment in the SWV strain. In both strains the first cervical vertebrae (Cl) appeared to provide the most sensitive index of teratogenic exposure.ConclusionsThis study provides evidence that a subteratogenic dose of caffeine can potentiate the teratogenic effect of acetazolamide in both C57BL/6J and SWV mice. However, strain associated, and therefore genetically based, differences in sensitivity were confirmed. Skeletal examinations provided evidence that treatment with both agents delayed fetal development in the more susceptible C57BL/6J strain, while reduction of ossification was less evident in the SWV strain. Thus, this parameter also reflects the greater resistance of the SWV strain to the interaction of acetazolamide and caffeine. Finally, these experiments support the idea that chemical interactions may, in part, be responsible for many birth defects of unknown etiology--a claim worthy of further investigation. / Department of Biology
5

Acetazolamide-induced Decrease Of Apical Fluid Flow In Choroid Plexus Is Independent Of The Concomitant Changes In Aquaporin-1 Expression

Ameli, Pouya Alexander 01 January 2010 (has links)
Acetazolamide (AZA), the only drug approved for treatment of hydrocephalus, is effective in only 25-30% of patients while its effect on fluid flow in the choroid plexus (CP) is unknown. The drug reversibly inhibits Aquaporin 4 (AQP4), the most highly expressed „water pore‟ in the brain, and it is postulated that it reduces cerebrospinal fluid (CSF) production by modulating AQP1 (mostly found in the apical membrane of the CP). In this study, we sought to elucidate the effect of AZA on AQP1 and fluid flow in CP. Primary CP culture from p10 Sprague-Dawley rats and TRCSF-B cell line were grown on Transwell permeable supports, treated with 100µM AZA or 100µM Vinpocetine (previously shown to increase AQP1 levels), and tested by: a) Fluid assays using TRITC-labeled Dextran to assay direction and extent of fluid flow; b) Immunoblot, Immunocytochemistry (ICC), and RT-PCR for AQP1 expression. Immnoblots and ICC analyses showed that AQP1 protein levels decrease in a delayed manner (lowest at 12 hours) with AZA treatment. The reduction in AQP1 protein was transient and preceded by a reduction in mRNA levels (lowest at 6 hours). Transwell fluid assays indicate a shift in fluid flow at 2 hours, prior to the changes in AQP1 mRNA or protein. Alteration of fluid flow by AZA (in both primary culture and TR-CSFB) is similar to Vinpocetine‟s effect in primary culture. Together with druginduced alterations in AQP1 levels, these data suggest independent mechanisms behind fluid flow and AQP1 expression.
6

Avaliação da fotoestabilidade de acetazolamida e loratadina e da capacidade de fotoproteção de seus complexos com ciclodextrinas / Assessing the photostability of acetazolamide and loratadine and the photoprotection capacity of its complexes with cyclodextrins

Rivas Granizo, Patricia Elizabeth 04 May 2012 (has links)
A fotoestabilidade é uma propriedade das moléculas que, quando utilizada como parâmetro farmacêutico, descreve como um fármaco responde à exposição à luz (solar ou artificial). No presente trabalho, foi avaliada a fotoestabilidade dos fármacos loratadina (LORA) e acetazolamida (ACZ) e de complexos LORA-ciclodextrinas. O estudo de fotoestabilidade de LORA (Capítulo 2) indicou que o fármaco é estável quando no estado sólido, porém, ocorre surgimento de coloração intensa. Por outro lado, quando em solução, observou-se degradação do fármaco, com surgimento de vários fotoprodutos denominados F1 a F15, dentre os quais foi possível identificar cinco compostos: F4 (C13H10N), F10 (C14H10CIN), F8 (C20H18CIN2O), F9 (C19H18CIN2) e F14 (C17H14CIN). A validação do método analítico CLAE, utilizado para quantificação de LORA em especialidades farmacêuticas (comprimidos e xaropes) é descrita no Capítulo 3. Na avaliação da fotodegradação forçada de formulações líquidas contendo LORA, foram degradados até 50% do fármaco. As formulações sólidas apresentaram-se fotoestáveis, observando-se perda de menos de 5% do fármaco. Não foram encontrados produtos de fotodegradação nas formulações, quando analisadas tal qual, obtidas do mercado. Dessa forma, as embalagens primárias garantiram sua estabilidade. A complexação de LORA com ciclodextrinas (Capítulo 4) mostrou-se um recurso bastante interessante para melhorar a fotoestabilidade do fármaco, uma vez que, após 12 horas de irradiação luminosa, é possível recuperar até 99% deste, quando na forma de complexo com &#947;-CD na proporção 1:1. Finalmente, o Capítulo 5 traz o método CLAE desenvolvido e validado para avaliação da acetazolamida (ACZ), o qual mostrou-se adequado para a quantificação do fármaco, obtendo-se ótima linearidade, precisão, exatidão e seletividade. Segundo as condições do guia Q1B, a ACZ se manteve estável quando submetida à radiação luminosa utilizando meios aquosos e no estado sólido. No entanto, a fotoestabilidade da ACZ foi afetada na presença de metanol, sendo possível quantificar três impurezas. / Photostability is a property of molecules that, when used as a pharmaceutical parameter, can describe how a drug responds to exposure to light (either solar or artificial). In this study, the photostability of the drugs loratadine (LORA) and acetazolamide (ACZ), as well as LORA-cyclodextrin complexes, was evaluated. A study of the photostability of LORA (Chapter 2) indicated that the drug is stable in its solid form, however intense coloring does occur. On the other hand, when in solution form, degradation of the drug was observed, with the appearance of several photoproducts that we labled F1 to F15, among which it was possible to identify five compounds: F4 (C13H10N), F10 (C14H10CIN), F8 (C20H18CIN2O), F9 (C19H18CIN2) and F14 (C17H14CIN). The validation of the analytical method by HPLC, used for the quantification of LORA in pharmaceutical products (tablets and syrups) is detailed in Chapter 3. In the evaluation of forced photodegradation of liquid formulations containing LORA, up to 50% of the drug was degraded. The solid formulations proved to be photostable, with a loss of less than 5% of the drug. No photodegradation products were found in the formulations when they were analyzed \"as is\" (the way they were obtained from the commercial market). Accordingly, their primary packaging protected their stability. The complexation of LORA with cyclodextrins (Chapter 4) proved to be an effective resource for improving the photostability of the drug, since, after 12 hours of luminous radiation, it was possible to recover up to 99% of the drug, when in the complex form with &#947;-CD, in the proportion 1:1. Finally, Chapter 5 describes the HPLC method developed and validated for the evaluation of acetazolamide (ACZ), which proved to be adequate for the quantification of the drug, with the attainment of optimal linearity, precision, exactness and selectivity. According to the conditions of the Q1B guideline, ACZ was stable when subjected to luminous radiation using aqueous means and in its solid state. However, the photostability of ACZ was affected by the presence of methanol, and we were able to quantify three impurities.
7

Synthesis of N-methyl acetazolamide and N-methyl methazolamide

Ahn, Christopher 01 January 2018 (has links)
Exposing Amyloid Beta 1-42 to neurons causes cell death. When carbonic anhydrase inhibitors (e.g. methazolamide or acetazolamide) are introduced along with 1-42 in a similar experiment, cell apoptosis is disrupted. However, when non-CA inhibitors are tested, (e.g. the indole derivative melatonin), the same disruption occurs. Are these carbonic anhydrase inhibitors acting on the same or a different pathway? One way to study the molecular mechanisms of these small molecule inhibitors is to modify their chemical structure. In this sense, when acetazolamide is methylated, apoptosis is resumed (Fossati et al., 2016). Finding a way to create N-methyl acetazolamide and N-methyl methazolamide through methylation procedures will lead to a better understanding of the pathways involved in neuronal apoptosis triggered by the Abeta peptide.
8

Avaliação da fotoestabilidade de acetazolamida e loratadina e da capacidade de fotoproteção de seus complexos com ciclodextrinas / Assessing the photostability of acetazolamide and loratadine and the photoprotection capacity of its complexes with cyclodextrins

Patricia Elizabeth Rivas Granizo 04 May 2012 (has links)
A fotoestabilidade é uma propriedade das moléculas que, quando utilizada como parâmetro farmacêutico, descreve como um fármaco responde à exposição à luz (solar ou artificial). No presente trabalho, foi avaliada a fotoestabilidade dos fármacos loratadina (LORA) e acetazolamida (ACZ) e de complexos LORA-ciclodextrinas. O estudo de fotoestabilidade de LORA (Capítulo 2) indicou que o fármaco é estável quando no estado sólido, porém, ocorre surgimento de coloração intensa. Por outro lado, quando em solução, observou-se degradação do fármaco, com surgimento de vários fotoprodutos denominados F1 a F15, dentre os quais foi possível identificar cinco compostos: F4 (C13H10N), F10 (C14H10CIN), F8 (C20H18CIN2O), F9 (C19H18CIN2) e F14 (C17H14CIN). A validação do método analítico CLAE, utilizado para quantificação de LORA em especialidades farmacêuticas (comprimidos e xaropes) é descrita no Capítulo 3. Na avaliação da fotodegradação forçada de formulações líquidas contendo LORA, foram degradados até 50% do fármaco. As formulações sólidas apresentaram-se fotoestáveis, observando-se perda de menos de 5% do fármaco. Não foram encontrados produtos de fotodegradação nas formulações, quando analisadas tal qual, obtidas do mercado. Dessa forma, as embalagens primárias garantiram sua estabilidade. A complexação de LORA com ciclodextrinas (Capítulo 4) mostrou-se um recurso bastante interessante para melhorar a fotoestabilidade do fármaco, uma vez que, após 12 horas de irradiação luminosa, é possível recuperar até 99% deste, quando na forma de complexo com &#947;-CD na proporção 1:1. Finalmente, o Capítulo 5 traz o método CLAE desenvolvido e validado para avaliação da acetazolamida (ACZ), o qual mostrou-se adequado para a quantificação do fármaco, obtendo-se ótima linearidade, precisão, exatidão e seletividade. Segundo as condições do guia Q1B, a ACZ se manteve estável quando submetida à radiação luminosa utilizando meios aquosos e no estado sólido. No entanto, a fotoestabilidade da ACZ foi afetada na presença de metanol, sendo possível quantificar três impurezas. / Photostability is a property of molecules that, when used as a pharmaceutical parameter, can describe how a drug responds to exposure to light (either solar or artificial). In this study, the photostability of the drugs loratadine (LORA) and acetazolamide (ACZ), as well as LORA-cyclodextrin complexes, was evaluated. A study of the photostability of LORA (Chapter 2) indicated that the drug is stable in its solid form, however intense coloring does occur. On the other hand, when in solution form, degradation of the drug was observed, with the appearance of several photoproducts that we labled F1 to F15, among which it was possible to identify five compounds: F4 (C13H10N), F10 (C14H10CIN), F8 (C20H18CIN2O), F9 (C19H18CIN2) and F14 (C17H14CIN). The validation of the analytical method by HPLC, used for the quantification of LORA in pharmaceutical products (tablets and syrups) is detailed in Chapter 3. In the evaluation of forced photodegradation of liquid formulations containing LORA, up to 50% of the drug was degraded. The solid formulations proved to be photostable, with a loss of less than 5% of the drug. No photodegradation products were found in the formulations when they were analyzed \"as is\" (the way they were obtained from the commercial market). Accordingly, their primary packaging protected their stability. The complexation of LORA with cyclodextrins (Chapter 4) proved to be an effective resource for improving the photostability of the drug, since, after 12 hours of luminous radiation, it was possible to recover up to 99% of the drug, when in the complex form with &#947;-CD, in the proportion 1:1. Finally, Chapter 5 describes the HPLC method developed and validated for the evaluation of acetazolamide (ACZ), which proved to be adequate for the quantification of the drug, with the attainment of optimal linearity, precision, exactness and selectivity. According to the conditions of the Q1B guideline, ACZ was stable when subjected to luminous radiation using aqueous means and in its solid state. However, the photostability of ACZ was affected by the presence of methanol, and we were able to quantify three impurities.
9

The Role of Carbonic Anhydrase in the Modulation of Central Respiratory-related pH/CO2 Chemoreceptor-stimulated Breathing in the Leopard Frog (Rana pipiens) Following Chronic Hypoxia and Chronic Hypercapnia

Srivaratharajah, Kajapiratha 26 February 2009 (has links)
The aim of this thesis was to elucidate the role of carbonic anhydrase (CA) in the modulation of central pH/CO2-sensitive fictive breathing (measured using in vitro brainstem-spinal cord preparations) in leopard frogs (Rana pipiens) following exposure to chronic hypercapnia (CHC) and chronic hypoxia (CH). CHC caused an augmentation in fictive breathing compared to the controls (normoxic normocapnic). Addition of acetazolamide (ACTZ), a cell-permeant CA inhibitor, to the superfusate reduced fictive breathing in the controls and abolished the CHC-induced augmentation of fictive breathing. ACTZ had no effect on preparations taken from frogs exposed to CH. Addition of bovine CA to the superfusate did not alter fictive breathing in any group, suggesting that the effects of ACTZ were due to inhibition of intracellular CA. Taken together, these results indicate that CA is involved in central pH/CO2 chemoreception and the CHC-induced increase in fictive breathing in the leopard frog.
10

The Role of Carbonic Anhydrase in the Modulation of Central Respiratory-related pH/CO2 Chemoreceptor-stimulated Breathing in the Leopard Frog (Rana pipiens) Following Chronic Hypoxia and Chronic Hypercapnia

Srivaratharajah, Kajapiratha 26 February 2009 (has links)
The aim of this thesis was to elucidate the role of carbonic anhydrase (CA) in the modulation of central pH/CO2-sensitive fictive breathing (measured using in vitro brainstem-spinal cord preparations) in leopard frogs (Rana pipiens) following exposure to chronic hypercapnia (CHC) and chronic hypoxia (CH). CHC caused an augmentation in fictive breathing compared to the controls (normoxic normocapnic). Addition of acetazolamide (ACTZ), a cell-permeant CA inhibitor, to the superfusate reduced fictive breathing in the controls and abolished the CHC-induced augmentation of fictive breathing. ACTZ had no effect on preparations taken from frogs exposed to CH. Addition of bovine CA to the superfusate did not alter fictive breathing in any group, suggesting that the effects of ACTZ were due to inhibition of intracellular CA. Taken together, these results indicate that CA is involved in central pH/CO2 chemoreception and the CHC-induced increase in fictive breathing in the leopard frog.

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