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PubMed1980

Active site-specific reconstituted copper(II) horse liver alcohol dehydrogenase: a biological model for type 1 Cu2+ and its changes upon ligand binding and conformational transitions.

Insertion of Cu2+ ions into horse liver alcohol dehydrogenase depleted of its catalytic Zn2+ ions creates an artificial blue copper center similar to that of plastocyanin and similar copper proteins. The esr spectrum of a frozen solution and the optical spectra at 296 and 77 K are reported, together with the corresponding data for binary and ternary complexes with NAD+ and pyrazole. The binary complex of the cupric enzyme with pyrazole establishes a novel type of copper proteins having the optical characteristics of Type 1 and the esr parameters of Type 2 Cu2+. Ternary complex formation with NAD+ converts the Cu2+ ion to a Type 1 center. By an intramolecular redox reaction the cuprous enzyme is formed from the cupric enzyme. Whereas the activity of the cupric alcohol dehydrogenase is difficult to assess (0.5%-1% that of the native enzyme), the cuprous enzyme is distinctly active (8% of the native enzyme). The implications of these findings are discussed in view of the coordination of the metal in native copper proteins.

Alcohol Oxidoreductases↗
PubMed1996

Inhibition of gap junction intercellular communications of cultured rat hepatocytes by ethanol: role of ethanol metabolism.

BACKGROUND/AIMS: In a previous study, we reported that in cultured rat hepatocytes, ethanol inhibits intercellular communication which is known to play a central role in the regulation of cell growth and differentiation. This work was designed to find out if ethanol exerts a direct action on cell membranes, comparable to other long-chain (C6-C9) alcohols, or an indirect action. METHODS: Intercellular communication was measured on short-term cultured rat hepatocytes by the fluorescent Lucifer-Yellow CH transfer method. Intracellular pH was measured by spectrofluorimetry and membrane expression of connexin 32 by indirect immunofluorescence. RESULTS: Under our conditions, ethanol (20 mM) inhibited intercellular communication of hepatocytes to the same extent as did octanol and 1 mM. Immunofluorescence semi-quantitative studies of connexin 32 suggested that the observed inhibition was not related to a decrease in the number of gap junction plaques. In contrast with those of octanol, the inhibitory effects of ethanol appeared to be indirect because the inhibition of ethanol metabolism by 4-methyl pyrazole abolished its effects on intercellular communication, while 4-methyl pyrazole did not influence the effects of octanol. Acetaldehyde, the main metabolite of ethanol was without effect on gap junctions. CONCLUSIONS: This suggests that the inhibition of intercellular communication induced by ethanol may be included among the consequences of intermediary cell metabolism disturbances indirectly due to ethanol oxidation. This may be one of the mechanisms by which ethanol metabolism exerts a hepatotoxic possibly carcinogenic action.

1-Octanol↗
PubMed1997

Genomic structure and expression analyses of serine acetyltransferase gene in Citrullus vulgaris (watermelon).

The genomic clones of Sat gene encoding serine acetyltransferase (SATase), a key enzyme in cysteine biosynthesis in plants, were isolated from the genomic library of Citrullus vulgaris (watermelon). The determination of nucleotide sequence of 5.7 kilobase pair (kbp) length revealed the presence of two introns of 1939 basepair (bp) and 515 bp length in the gene. The transcription start point was determined by primer extension experiments. Southern blot analysis indicated the presence of a single copy of the Sat gene and a couple of additional related sequences in the genome of C. vulgaris. The expression of Sat was analyzed in watermelon plants growth under sulfur- and/or nitrogen-starved conditions and in the presence of pyrazole, O-acetylserine and N-acetylserine. Only slight increment (ca. 1.5-2-fold) of Sat gene expression was observed upon sulfur starvation for 48 h. Interestingly, the addition of pyrazole, which is a precursor of beta-pyrazolealanine (beta-PA) synthesized by SATase and cysteine/beta-PA synthase, enhanced the expression of Sat by ca. 2-fold.

Acetyltransferases↗
PubMed2001

Validation of a chromatographic method to determine E-6006 and its metabolite E-6332 in rat and dog plasma by solid-phase extraction and capillary gas chromatography. Application in pharmacokinetics.

E-6006, 5-(alpha-[2-(dimethylamino)ethoxy]-2-thienylmethyl)-1-methyl-1H-pyrazole is a new antidepressive compound and E-6332, 5-(alpha-[2-(methylamino)ethoxy]-2-thienylmethyl)-1-methyl-1H-pyrazole is its desmethylate metabolite. With the aim of quantifying E-6006 and E-6332, simultaneously in rat or dog plasma, a method of analysis based on solid-phase extraction coupled with capillary gas chromatographic system with N-P detection was developed and validated. E-6006, E-6332 and its internal standard (E-4018) were isolated from plasma using an off-line semiautomatic solid-phase extraction method. Gas chromatography separations were carried out by means of 12 m length, 0 2 mm (i.d.) and 0.33 microm (f.t.) ULTRA 1 type capillary column in splitless mode of injection at 190 degrees C, with a TSD or specific nitrogen--phosphorus detector. No peaks interfering with the quantification of E-6332 and E-6006 were observed. The limit of quantification was 5 ng/ml with a precision and accuracy <17%. The peak height ratios were proportional to E-6332 and E-6006 concentration over the range from 5 to 600 ng/ml (r(2)>0.998). Mean recoveries of E-6332, E-6006 and internal standard from rat plasma were between 57.1 and 82.6. Intra-assay precision coefficients were <8.0 and <11.8%, respectively, for E-6332 and E-6006, with an accuracy <12.6 and <9.7%. Both inter-assay precision and accuracy were within acceptable limits (<15%). In dog, the results were very similar to those obtained in rat. To show an example of the suitability of the method to determine E-6332 and E-6006, plasma profiles obtained after single oral and intravenous administration of 20 mg/kg to rats and 25 mg/kg to dogs are reported.

Animals↗
PubMedDate not supplied

Repeated ethanol withdrawal experience increases the severity and duration of subsequent withdrawal seizures in mice.

Repeated ethanol withdrawal experience has been shown to result in an exacerbation of future withdrawal episodes. This sensitization of the withdrawal response has been hypothesized to represent a "kindling" phenomenon. The present study was designed to examine whether a systematic increase in the number of previous ethanol withdrawal experiences increases both the severity and duration of a subsequent withdrawal response. An established model of repeated ethanol intoxication/withdrawal was employed in which adult C3H mice were chronically exposed to ethanol vapor in inhalation chambers. In the first experiment, multiple withdrawal (MW) groups of mice received nine (MW x 9), six (MW x 6), or three (MW x 3) cycles of 16-h ethanol vapor separated by 8-h periods of abstinence prior to testing: a single withdrawal (SW) group was tested following a single bout of 16-h ethanol exposure; and a control (C) group did not receive any ethanol treatment throughout the experiment. In a second experiment, a group of mice (MW1-9) were repeatedly tested over nine cycles of withdrawal. A third experiment was designed to assess the effects of repeated pyrazole administration on the potentiated withdrawal seizure response. Results indicated a positive relationship between the number of previously experienced ethanol withdrawals and the severity and duration of a subsequent withdrawal episode. Blood ethanol levels were similar for all ethanol-exposed groups prior to withdrawal assessment. Further, the intensity of withdrawal seizures (handling-induced convulsions) progressively increased over nine cycles of intoxication/withdrawal and repeated testing did not significantly influence the development of this potentiated response. In addition, repeated administration of pyrazole did not appear to influence this withdrawal sensitization phenomenon. Collectively, these results provide further support for the "kindling" hypothesis of ethanol withdrawal.

Administration, Inhalation↗
PubMed2003

Synthesis and antimycotic activity of N-azolyl-2,4-dihydroxythiobenzamides.

N-pyrazole and N-1,2,4-triazole derivatives of 2,4-dihydroxythiobenzamide prepared from sulfinyl-bis-(2,4-dihydroxythiobenzoyl) and commercially available azole amines were tested for their antimycotic activity. The chemical structure of compounds was confirmed by IR, 1H NMR, MS and elemental analysis. The MIC values against the reference strain Candida albicans ATCC 10231, azole-resistant clinical isolates of Candida albicans and non-Candida albicans species were determined for their potential activity in vitro. The compounds exhibited comparable or higher activity than itraconazole and fluconazole tested under the same experimental conditions. Pyrazoline derivatives showed higher activity than other analogues. The strongest fungistatic activity for N-(2,3-dimethyl-1-phenyl-1,2-dihydro-5-oxo-5H-pyrazol-4-yl)-2,4-dihydroxythiobenzamide was found with MIC values significantly lower than those for the studied drugs.

Antifungal Agents↗
PubMed2003

Synthesis and muscarinic activities of O-[(benzyl- or benzoyl-pyrazolyl)propynyl]-oximes of N-methylpiperidinone, 3-tropinone, and 3-quinuclidinone.

The synthesis of O-propynyloximes of N-methylpiperidinone, 3-tropinone, and 3-quinuclidinone, containing several pyrazole frameworks is described, together with their muscarinic receptor affinities. Compounds derived from N-methylpiperidinone or 3-tropinone and N-(4-methoxybenzyl)- or N-(2,4,6-trimethylbenzoyl)pyrazole showed moderate activity for muscarinic receptors in the rat central nervous system. A semi-empirical AM1 calculation has shown that the O-[(benzoyl-pyrazolyl)propynyl]-oximes of tropinone fit a previously described muscarinic pharmacophoric model, revealing structural features useful for the development of new muscarinic agents.

Animals↗
PubMed2004

Safety of the new selective cyclooxygenase type 2 inhibitors rofecoxib and celecoxib in patients with anaphylactoid reactions to nonsteroidal anti-inflammatory drugs.

BACKGROUND: Controlled oral challenge with nonsteroidal anti-inflammatory drugs (NSAIDs) is the only definite way to detect safe NSAIDs in patients with NSAID-induced anaphylactoid reactions. OBJECTIVE: To evaluate the safety of the selective cyclooxygenase (COX) type 2 inhibitors rofecoxib and celecoxib in patients with single-reactive, NSAID-induced anaphylactoid reactions. METHODS: We prospectively conducted single-blind, placebo-controlled oral challenges (SBPCOCs) with rofecoxib and celecoxib in 33 patients with single-reactive, NSAID-induced anaphylactoid reactions. RESULTS: Nineteen women and 14 men (age range, 20-78 years; mean age, 44.8 years) exhibited anaphylactoid reactions on emergency department admission. Symptoms involved the skin (100%), laryngeal edema (73%), systolic hypotension (39%), and the gastrointestinal system (15%). The NSAIDs most frequently involved in the episodes were dipyrone (64%), propyphenazone (12%), and diclofenac (12%). In all patients, tolerance to a potent, nondiscriminatory COX inhibitor (except those reported as being responsible for the reaction) was noted. The SBPCOCs with the selective COX-2 inhibitors celecoxib and rofecoxib were well tolerated in all cases. Twenty-three patients who had an anaphylactoid reaction involving dipyrone and propyphenazone showed good tolerance to celecoxib (which contains a pyrazole group in its structure) on challenge. CONCLUSIONS: The SBPCOCs with highly selective COX-2 inhibitors were safe in patients with single-reactive, NSAID-induced anaphylactoid reactions, even in cases that involved pyrazole derivatives.

Adult↗
PubMed1989

Mouse steroid 15 alpha-hydroxylase gene family: identification of type II P-450(15)alpha as coumarin 7-hydroxylase.

We identified type II P-450(15)alpha as mouse coumarin 7-hydroxylase (P-450coh). Unlike type I P-450(15)alpha, the other member within the mouse steroid 15 alpha-hydroxylase gene family, type II catalyzed little steroid 15 alpha-hydroxylase activity, yet structurally there were only 11 substitutions between type I and type II P-450(15)alphaS within their 494 amino acid residues (Lindberg et al., 1989), and the N-terminal sequence (21 residues) of P-450coh was identical with that of both P-450(15)alphaS. Induction by pyrazole of coumarin 7-hydroxylase activity correlated well with the increase of type II P-450(15)alpha mRNA in 129/J male and female mice. Pyrazole, on the other hand, was less in males or not effective in females in inducing the 15 alpha-hydroxylase activity and type I P-450(15)alpha mRNA. Expression of type I and II in COS-1 cells revealed that the latter catalyzed coumarin 7-hydroxylase activity at 10 to approximately 14 pmol min-1 (mg of cellular protein)-1. The former, on the other hand, had a high testosterone 15 alpha-hydroxylase but little coumarin 7-hydroxylase activity. It was concluded, therefore, that type II P-450(15)alpha is the mouse coumarin 7-hydroxylase. Identification of type II as the P-450 specific to coumarin 7-hydroxylase activity and characterization of its cDNA and gene, therefore, were significant advances toward understanding the basis of genetic regulation of this activity in mice (known as Coh locus).

Animals↗
PubMed1981

Glutamate as the common precursor for the aglycon of the naturally occurring C-nucleoside antibiotics.

Pyrazofurin is one of four naturally occurring C-nucleoside antibiotics; it is elaborated by Streptomyces candidus. The biosynthesis of the pyrazole ring of pyrazofurin has been studied by using 13C- and 14C-labeled acetate. Carbon-13 incorporation into pyrazofurin was observed by proton-decoupled 13C Fourier transform NMR spectroscopy. The incorporation of 14C from [1-14C]acetate was 0.7%. The enrichment of carbons 3, 4, and 5 of pyrazofurin from [2-13C]acetate by S. candidus confirms earlier findings that acetate is converted to glutamate by the combined action of the Krebs cycle and malic enzyme [Elstner, E. F., Suhadolnik, R. J., & Allerhand, A. (1973) J. Biol. Chem. 248, 5385]. Malic enzyme will give rise to [1,2-13C]acetate from [2-13C]acetate. The [1,2-13C]acetate is then converted to glutamate labeled with 13C in carbons 2--5. The 13C incorporation data indicate that carbons 1, 2, 3, and 4, but not 5, of glutamate serve as the four-carbon donor for the carboxamide carbon, C-5, C-4, and C-3, respectively, of the pyrazole ring of pyrazofurin.

Acetates↗
PubMedDate not supplied

Solid-phase synthesis of substituted guanidines using a novel acid labile linker.

A novel acid labile linker for solid-phase synthesis of substituted guanidines has been developed. Its synthetic utility is exemplified by high-yielding pyrazole displacement with structurally and electronically diverse sets of aliphatic and aromatic amines. The final cleavage is achieved by treatment with 95:5 trifluoroacetic acid/water for 1 h. The corresponding guanidines were obtained in high purity (80-95%) and good isolated yields (50-95%). The scope and limitations of this linker were further demonstrated by the solid-phase synthesis of an 880-member library of individual trisubstituted arylguanidines employing pyrazole displacement with a set of 11 anilines and two subsequent Mitsunobu N-alkylations with sets of 10 and 8 alcohols, respectively.

Amines↗
PubMedDate not supplied

Prediction of multiple binding modes of the CDK2 inhibitors, anilinopyrazoles, using the automated docking programs GOLD, FlexX, and LigandFit: an evaluation of performance.

Anilinopyrazoles as CDK2 inhibitors can adopt multiple binding modes depending on the substituents at the 5-position of the pyrazole ring, based on CDK2/cyclin A crystallographic studies. Three commercially available docking programs, FlexX, GOLD, and LigandFit, were tested with 63 anilinopyrazole analogues in an attempt to reproduce the binding modes observed in the crystal structures. Each docking program gave different ligand conformations depending on the scoring or energy functions used. FlexX/drugscore, GOLD/chemscore, and LigandFit/plp were the best combinations of each docking program in reproducing the ligand conformations observed in the crystal structures. The 63 analogues were divided into two groups, type-A and type-B, depending on the substituent at the 5-position of the pyrazole ring. Although an alternate binding mode, observed in a crystal structure of one type-B compound, could not be reproduced with any of the above docking/scoring combinations, GOLD, with a template constraint based on the crystal structure coordinates, was able to reproduce the pose. As for type-A compounds, all docking conditions yielded similar poses to those observed in crystal structures. When predicting activities by scoring programs, the combination of docking with LigandFit/plp and scoring with LIGSCORE1_CFF gave the best correlation coefficient (r=0.60) between experimental pIC50 values and top-ranked rescores of 30 poses of each compound. With regard to type-A compounds, the correlation was 0.69. However, when 11 compounds, whose top-ranked rescored poses did not demonstrate the correct binding modes in reference to the crystal structure, were removed, the correlation rose to 0.75. Consequently, predicting activity on the basis of correct binding modes was found to be reliable.

Algorithms↗
PubMed2002

Metal-induced cyclization of thiosemicarbazones derived from beta-keto amides and beta-keto esters: open-chain and cyclized ligands in zinc(II) complexes.

The reactions of Zn(OAc)(2) with acetoacetanilide, methyl acetoacetate, o-acetoacetanisidide, and ethyl 2-methylacetoacetate thiosemicarbazones (HTSC(1), HTSC(2), HTSC(3), and HTSC(4), respectively) were explored in methanol. With HTSC(1), HTSC(2), and HTSC(3), following isolation of the corresponding zinc(II) thiosemicarbazonates [Zn(TSC(x))(2)] (x = 1, 2, 3), the mother liquors afforded pyrazolonate complexes [ZnL(1)(2)(H(2)O)] (HL(1) = 2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothioamide) that had been formed by cyclization of the corresponding TSC(-). The reaction of HTSC(4) with zinc(II) acetate gave only the pyrazolonate complex [ZnL(2)(2)(H(2)O)] (HL(2) = 2,5-dihydro-3,4-dimethyl-5-oxo-1H-pyrazole-1-carbothioamide). All compounds were studied by IR and NMR spectroscopy, and HTSC(3), [Zn(TSC(3))(2)] x DMSO, [ZnL(1)(2)(H(2)O)] x 2DMSO, and [ZnL(2)(2)(H(2)O)] x 2DMSO were also studied by X-ray diffractometry, giving a thorough picture of the cyclization process. In preliminary tests of the effects of HL(1) and [ZnL(1)(2)(H(2)O)] on rat paw inflammatory edema induced by carrageenan, HL(1) showed antiinflammatory activity.

Amides↗
PubMed2002

Tuning and dissecting electronic and steric effects in ammonium receptors: nonactin vs artificial receptors.

Ion selective electrodes (ISE) based on three different tripodal receptors (5, 6, and 7) have been investigated for sensing ammonium ion. Each receptor is based on three pyrazole groups that can accept three H-bonds from the bound ammonium ion. The receptor based on 4-bromo-3,5-dimethylpyrazole (6) is the most sensitive with a detection limit for ammonium ion of 2.5 x 10(-5) M at pH 8. The detection limits for the receptors based on 2,3-dimethylpyrazole (5) and unsubstitued pyrazole (7) are 1.0 x 10(-4) and 2.0 x 10(-4) M, respectively. The selectivities of the receptors 5, 6, and 7 for sensing ammonium ion over potassium ion (logK(NH)4+(/K)+) are -2.8, -2.3, and -1.7, respectively. In contrast, the detection limit and the selectivity of a nonactin-based ISE are 2.2 x 10(-5) M and -1.3, respectively. Crystallographic studies reveal that 6 accepts three H-bonds from the bound ammonium and singly protonated receptor 5 forms three H-bonds with the bound water molecule.

Anti-Bacterial Agents↗
PubMed2004

Sorption and degradation of azimsulfuron on iron(III)-rich soil colloids.

The sorption of N-[[(4,6-dimethoxypyrimidin-2-yl)amino]carbonyl]-1-methyl-4-(2-methyl-2H-tetrazole-5-yl)1H-pyrazole-5-sulfonamide (AZS) on an iron oxide, iron(III)-humate, and an Fe3+-saturated clay was studied using a batch equilibrium method. Generally, 20 mg of each colloid was equilibrated with 20 mL of AZS solution (1.5-12.7 microM). The sorption on iron-montmorillonite and iron oxide was rapid, and the equilibrium was attained within 1.5 and 5 h, respectively. In the case of Fe-saturated humic acid the equilibrium time was 20 h. After equilibration, the phases were centrifuged (19000g, 15 min) and the supernatant was sampled and analyzed by HPLC. The values of Freundlich constants indicate that iron oxide (Kads = 199.5) shows the highest sorptive capacity toward AZS, followed by iron(III)-clay (Kads = 146.6) and iron(III)-humate (Kads = 108.2). With elapsing time, AZS degradation was observed in all colloidal suspensions. Iron-humate (t(1/2) = 136 h) is most effective in promoting AZS degradation, followed by iron oxide (t(1/2) = 204 h) and iron-clay (t(1/2) = 385 h). The metabolites 2-amino-4,6-dimethoxypyrimidine and 1-methyl-4-(2-methyl-2H-tetrazole-5-yl)-1H-pyrazole-5-sulfonamide, arising from a hydrolytic cleavage of the sulfonylurea bridge, were the only byproducts observed. A Fourier transform infrared study suggests that the sorption of AZS on iron-clay involves the protonation of one of the two basic pyrimidine nitrogens induced by the acidic water surrounding the saturating Fe3+ ions. Instead, the formation of a six-membered chelated complex favors the sorption of AZS on iron oxide.

Adsorption↗
PubMed1980

Alkylating nucleosides. 4. Synthesis and cytostatic activity of chloro- and iodomethylpyrazole nucleosides.

The synthesis and cytostatic activity of several chloromethyl- and iodomethylpyrazole nucleosides are described. Glycosylation of ethyl 3(5)-(chloromethyl)pyrazole-5(3)-carboxylate (3) and 3(5)-(chloromethyl)pyrazole-5(3)-carboxamide (4) with poly(O-acetylated) sugars via an acid-catalyzed fusion method gave the corresponding 3-(chloromethyl)-5-carboxylate and 3-(chloromethyl)-5-carboxamide substituted nucleosides 7 and 9, respectively. From the reaction of 4 with tetra-O-acetyl-beta-D-ribofuranose, the 5-(chloromethyl)-3-carboxamide-substituted derivative 11 was also obtained. Reaction of 7, 9, and 11 with sodium iodide in acetone provided the related iodomethylpyrazole nucleosides 8, 10, and 12. In general, chloromethyl-substituted nucleotides showed moderate activities against HeLa cells, while all the corresponding iodomethyl derivatives exhibited high activities. Some of these latter compounds increased the life span of mice bearing ECA tumor.

Alkylating Agents↗
PubMed1982

Synthesis and enzymic activity of various substituted pyrazolo[1,5-a]-1,3,5-triazines as adenosine cyclic 3',5'-phosphate phosphodiesterase inhibitors.

A series of various pyrazolo[1,5-a]-1,3,5-triazines have been prepared and studied as inhibitors of cAMP phosphodiesterase isolated from bovine brain, bovine heart, and rabbit lung. A number of compounds were found to be superior to theophylline. 2-Ethyl-7-phenylpyrazolo[1,5-a]-1,3,5-triazine (35) was found to be 97 times more potent than theophylline as an inhibitor of bovine brain PDE. 8-Bromo-2,4-dimethyl-7-phenylpyrazolo[1,5-a]-1,3,5-triazine (52) showed alpha lung = 40 compared to alpha heart = 3.0. Thus, various substituents could increase or decrease the inhibition relative to the type and source of tissue from which the PDE was isolated. The most active compound was 8-bromo-4-(diethylamino)-7-phenylpyrazolo[1,3-a]-1,3,5-triazine (25), which was 185 times more potent than theophylline as an inhibitor of PDE isolated from rabbit lung. The stepwise synthesis via ring-closure procedures of requisite pyrazole intermediates, followed by electrophilic substitution in the pyrazole ring and/or nucleophilic substitution in the 1,3,5-triazine moiety, resulted in the various pyrazolo[1,5-a]1,3,5-triazines listed in Tables I and II. Structure-activity relationships are reviewed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Carbonic anhydrase activators: design of high affinity isozymes I, II, and IV activators, incorporating tri-/tetrasubstituted-pyridinium-azole moieties.

A series of tight binding carbonic anhydrase (CA) activators was obtained by reaction of amino-azoles (3-amino-pyrazole, 2-amino-imidazole, and 5-amino-tetrazole) with tri- or tetrasubstituted pyrylium salts. Many of the new pyridinium salts incorporating azole moieties reported here proved to be efficient in vitro activators of three CA isozymes, CA I, II, and IV. Very good activity was detected against hCA I and bCA IV (h = human; b = bovine isozymes), for which some of the new compounds showed affinities in the low nanomolar range, whereas against hCA II, their affinities were in the range of 95-150 nM. Substitution patterns of the pyridinium ring leading to best activity included 4-phenyl-2,6-dialkyl moieties or 2,4,6-tri- and 2,3,4,6-tetraalkyl groups. Ex vivo experiments showed some of the new activators to strongly enhance CA activity after incubation with human erythrocytes. Furthermore, due to their cationic nature, some of these compounds (the imidazole and pyrazole derivatives) are membrane-impermeant, discriminating thus between cytosolic and membrane-bound CA isozymes. The present paper is the first report of membrane-impermeant CA activators. The pyridinium tetrazole derivatives on the other hand do penetrate through biological membranes. Such CA activators might lead to the development of drugs/diagnostic tools for the management of CA deficiency syndromes as well as for the pharmacological enhancement of synaptic efficacy, spatial learning, and memory. This may constitute a new approach for the treatment of Alzheimer disease and other conditions in need of achieving memory therapy.

Animals↗