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PubMed1979

Control of renal bicarbonate transport.

Single rabbit renal tubules were perfused in vitro to elucidate the factors that control bicarbonate transport. One factor studied was the preexisting acid-base status of the rabbits. Cortical collecting ducts from acidotic rabbits (given ammonium chloride) transported bicarbonate from lumen to bath. Collecting ducts from alkalotic rabbits (given sodium bicarbonate) transported bicarbonate in the opposite direction. Thus, bicarbonate transport by collecting ducts in vitro was conditioned by the preexisting state of the rabbit in vivo. In contrast, bicarbonate transport by proximal straight tubules and cortical thick ascending limbs was not affected by ammonium chloride or sodium bicarbonate given to the rabbits. Parathyroid hormone, the second factor studied, strongly inhibited bicarbonate absorption by proximal straight tubules.

Absorption↗

PubMed1984

Uncoating of influenza virus in endosomes.

The intracellular uncoating site of influenza virus was studied by measuring the fluorescence intensity of probes conjugated to the virus or the isolated hemagglutinin and also by assaying virus replication under various incubation conditions. Acidification of the viral environment was monitored by the decrease in the fluorescence intensity of fluorescein isothiocyanate, and transport of the virus particles into secondary lysosomes was assayed by the increase in the fluorescence intensity of fluorescein isothiocyanate diphosphate. The intracellular pH was estimated by the ratio of fluorescence intensities excited at two different wavelengths. It was found that the viral environment became acidified to a pH value of 5.1 to 5.2 within 10 min at 37 degrees C or 1 h at 20 degrees C after endocytosis. Addition of ammonium chloride to the medium rapidly raised the pH to 6.7. Transport of the virus particles into the secondary lysosomes was slower and negligibly low during those incubation periods. Virus replication occurred when the cells were incubated for 10 min at 37 degrees C or for 1 h at 20 degrees C, followed by incubation in the presence of ammonium chloride for a total of 12 h. These results indicate the uncoating of influenza virus in endosomes before reaching the secondary lysosomes.

Animals↗

PubMed1986

Urine pH and the relationship between urine flow and urinary prostaglandin E excretion in the rat.

The relationship between urine flow and urinary prostaglandin E (PGE) excretion was investigated at constant urine pH in the anaesthetized rat. The urine pH was maintained at approximately pH 6 or pH 8 by the intravenous infusion of either ammonium chloride or sodium bicarbonate respectively. Two distinct patterns in the relationship between PGE excretion and urine flow were observed. The first showed a fall in urinary PGE excretion as the urine flow increased over the low flow range of 2-5 ml/h, and was common to both experiments. The second relationship, however, showed a marked difference between the ammonium chloride and sodium bicarbonate experiments since: (a) in acidic urine (pH 6), PGE excretion increased (P less than 0.002) with the urine flow, attaining a rate of 87 +/- 6 pmol/h (n = 6) at the highest level of flow achieved (12 ml/h); (b) in alkaline urine (pH 8), PGE excretion was significantly (P less than 0.01) higher but did not increase with urine flow, remaining constant at approximately 90 pmol/h (n = 6). The lack of any additive effect on urinary PGE excretion between increasing the urine flow and making the urine alkaline may be explained by both stimuli acting through a common mechanism, a concept which is consistent with the hypothesis that PGE may be reabsorbed in the distal nephron. The flow-dependency of urinary PGE excretion could therefore result from a reduction in reabsorption rather than the increase in passive secretion proposed previously.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Morphological and proliferative responses of cultured Schwann cells following rapid phagocytosis of a myelin-enriched fraction.

Cultured Schwann cells were found to phagocytose exogenously applied myelin membranes within 1 h. However, the resulting proliferative response required an additional 9 h of incubation. Treatment with ammonium chloride, a lysosomal inhibitor, delayed the appearance of the proliferative response to the myelin membranes by 12 h. Processing of myelin within the Schwann cells was followed by the appearance of immunocytochemically detectable myelin basic protein which was first visible at 4 h. Similar to the proliferative response, the appearance of immunoreactive material was delayed by the addition of ammonium chloride. Schwann cells were observed initially to ingest myelin fragments at their distal-most tips after which time the myelin phagosomes collected in the perinuclear region and fused with lysosomes. Phagocytic Schwann cells had a notable increase in Golgi membranes and microfilaments and contained widely dilated, rough endoplasmic reticulum cisternae. In purified cell cultures, Schwann cells phagocytosed myelin slower than macrophages, but displayed phagocytic abilities much greater than fibroblasts. The ability of cultured Schwann cells to phagocytose myelin rapidly suggests that these cells may aid in the breakdown and removal of myelin during Wallerian degeneration. These data further confirm the mitogenic effect of myelin and its possible role during nerve regeneration.

Animals↗

PubMed2002

[Optimalization for preparation and expansion of ex vivo human umbilical blood cells for transplantation].

This work was aimed at finding optimal conditions for isolation and storage of hematopoietic cells from umbilical cord blood and checking the usefulness of ex vivo expansion in a serum-free medium. Mononuclear cells were isolated either by density gradient centrifugation (Ficoll-Histopaque or Gradisol L) or by hypoosmotic lysis of erythrocytes and granulocytes in ammonium chloride. Toxicity of metabolic dyes (Hoechst 33342, Rhodamine 123, Pyronine Y) used in flow cytofluorimetry and the effects of freezing in dry ice or in a mechanical freezer with and without a methanol bath were compared. The influence of ex vivo expansion of cells in a serum-free medium on their proliferative potential and apoptosis was investigated. In comparison with ammonium chloride, density gradient centrifugation both in Ficoll-Histopaque and Gradisol L offered superior and consistent results as to cell yield, vitality and proliferative potential. Hoechst 33342 demonstrated the highest toxicity with CD34+ cells, disqualifying this dye for transplantation purposes. Mechanical freezing with prior methanol bath was found to be the safest method of storage. The concentration of TGF beta released by cells subjected to expansion ex vivo in a serum-free medium was markedly elevated and correlated with the percentage of apoptotic cells. Furthermore, the proliferative potential of cells deteriorated as a result of expansion.

Blood Preservation↗

PubMed1985

Stimulation of an N-ethylmaleimide-sensitive ATPase in the collecting duct segments of the rat nephron by metabolic acidosis.

A plasma membrane ATPase sensitive to inhibition by N-ethylmaleimide (NEM) and insensitive to inhibition by oligomycin and ouabain has been shown to be involved in acidification of urine in the turtle bladder. The activity of this NEM-sensitive ATPase was determined in four types of distal nephron segments of normal rats and in rats treated with ammonium chloride. The enzyme activity was determined by a fluorometric micromethod in which ATP hydrolysis was coupled to NADH oxidation. Significant activities (10-35 pmol ADP X min-1 X mm-1) of NEM-sensitive ATPase were present in the distal convoluted tubule (DCT) and in the cortical and outer and inner medullary collecting duct segments of normal rats. In metabolic acidosis produced by ammonium chloride treatment (plasma CO2 content = 15.3 +/- 0.8 mequiv./L), the NEM-sensitive ATPase activity was increased significantly (60-100%) in the collecting duct segments without showing a significant change in the enzyme activity in the DCT. Our data are consistent with the hypothesis that a plasma membrane H+-ATPase (inhibited by NEM but not by oligomycin or ouabain) is involved in H+ secretion in the mammalian collecting duct.

Acidosis↗

PubMed1994

Enhanced Na(+)-H+ exchanger activity and NHE-1 mRNA levels in human lymphocytes during metabolic acidosis.

It has recently been demonstrated that uremic metabolic acidosis and experimental metabolic acidosis caused by ingestion of ammonium chloride coincide with increased Na(+)-H+ exchanger (NHE-1) activity in human blood cells. In the present study, we investigated whether an increased level of NHE-1 specific mRNA in human lymphocytes during the course of an experimental metabolic acidosis could explain the enhanced transport activity during metabolic acidosis. Six healthy individuals were studied before and after 5 days of taking 15 g of ammonium chloride daily. Plasma pH and bicarbonate decreased significantly, from 7.42 +/- 0.027 to 7.28 +/- 0.05 and from 26.7 +/- 2.0 to 15.6 +/- 2.9 mM, respectively. Basal cytosolic pH (pHi) and Na(+)-H+ exchange activity were measured in lymphocytes loaded with the fluorescent pHi indicator 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. Basal pHi remained unchanged during metabolic acidosis (7.03 +/- 0.07 vs. 7.03 +/- 0.06). Ethylisopropylamiloride-sensitive pHi recovery increased from 0.046 +/- 0.007 to 0.076 +/- 0.012 dpHi/min (P < 0.0001). The transcript level of NHE-1 mRNA was measured by reverse-transcription polymerase chain reaction in comparison with a constitutively expressed reference gene (glyceraldehyde-3-phosphate dehydrogenase). NHE-1 mRNA in human lymphocytes increased 1.5-fold in metabolic acidosis. These data suggest that the increased Na(+)-H+ exchange activity in metabolic acidosis may be caused by de novo synthesis of antiport protein.

Acidosis↗

PubMed2004

Validating sample preservation techniques and holding times for the approved compliance monitoring methods for haloacetic acids under the US EPA's stage 1 D/DBP rule.

Haloacetic acids (HAAs), which are formed during the disinfection of drinking waters with chlorine, are regulated by the US Environmental Protection Agency (EPA) under the Stage 1 Disinfectant/Disinfection Byproducts (D/DBP) Rule. Recently, three studies have been reported indicating that low concentrations of HAAs can also be formed during disinfection with chloramines. Methods currently approved for compliance monitoring under the Stage 1 Rule arrest the chlorine-mediated formation of HAAs by adding ammonium chloride, which forms chloramines. Studies were undertaken using an in-process water that favored the formation of HAAs with moderate total organic carbon concentration and high levels of chlorine to investigate the potential formation of HAAs under sample storage conditions. The ammonium chloride-quenched sample did form a small amount of HAAs, but total formation over a period equal to the 14-day sample storage time was less than 2 microg/l, whereas the unquenched samples increased 41 microg/l during the same period. Pour plate studies indicated that chlorinated drinking waters quenched with ammonium chloride are protected from microbial growth, which is an important additional advantage to this preservation scheme. The presence of a combined chlorine residual should prevent microbial degradation of HAAs in samples. These studies support the preservation protocols and the sample storage times promulgated for compliance monitoring under the Stage 1 D/DBP Rule.

Acetic Acid↗

PubMed1994

The cytoplasmic domain of P-selectin contains a sorting determinant that mediates rapid degradation in lysosomes.

P-selectin is a cell adhesion molecule required transiently on the surface of activated platelets and endothelial cells as a receptor for leukocytes. It is stored in secretory granules in platelets, endothelial cells, and transfected neuroendocrine cells and is rapidly delivered to the plasma membrane upon exocytosis of the secretory granules. It is then rapidly internalized in endothelial cells and transfected cells. We find that in transfected neuroendocrine PC12 cells, the fraction of P-selectin that is not targeted to secretory granules is rapidly degraded. In transfected CHO fibroblasts, which lack secretory granules, P-selectin was degraded with a half time of 2.3 h in plated cells, while low density lipoprotein receptor (LDL-R) had a half life of 9 h. In cells cultured in ammonium chloride to inhibit lysosomal proteinases, P-selectin was protected from degradation and rapidly accumulated in vesicles enriched in lgp-B, a resident lysosomal membrane protein. The cytoplasmic domain of P-selectin was sufficient to confer rapid turnover on LDL-R. Deletion of 10 amino acids from the cytoplasmic domain of P-selectin extended the half life to 9.5 h and abrogated rapid lysosomal targeting in the presence of ammonium chloride, implicating this sequence as a necessary element of a novel lysosomal targeting signal. The rate limiting step in degradation occurred after internalization from the cell surface, indicating that sorting of P-selectin away from efficiently recycled proteins occurs in endosomes. We propose that this sorting event represents a constitutive equivalent of receptor down regulation, and may function to regulate the expression of P-selectin at the surface of activated endothelial cells.

Amino Acid Sequence↗

PubMed1992

Characteristics of large neutral amino acid-induced release of preloaded L-glutamine from rat cerebral capillaries in vitro: effects of ammonia, hepatic encephalopathy, and gamma-glutamyl transpeptidase inhibitors.

The release of newly loaded L-[14C]glutamine (L-Gln) from rat cerebral cortical capillaries was stimulated by L-transport system substrates: tryptophan (TRY), leucine (leu), and nonlabeled L-Gln, respectively, by 32, 50, and 40% above the basal release resulting from superfusion with standard Krebs-Henseliet buffer. However, no stimulation was observed upon treatment with D-Gln or L-glutamate (L-Glu), which are not the L-system substrates, or with ammonium chloride. The stimulatory effect of TRY was temperature dependent but sodium independent, and was abolished in the presence of a sulfhydryl reagent N-ethylmaleimide (NEM). The results support the view that the L-Gln-stimulated uptake of large neutral amino acids (LNAA) across the blood-brain barrier involves the L-system mediated Gln-LNAA exchange. The TRY-stimulated Gln release was enhanced in vitro by simultaneous addition of ammonium chloride, and in capillaries derived from rats with acute hepatic encephalopathy (HE). These results confirm the role of Gln-LNAA exchange in the excessive accumulation of LNAA in brain observed in a variety of hyperammonemic conditions. Superfusion of L-Gln-loaded capillaries in a buffer containing gamma-glutamyl transpeptidase (GGT) inhibitors, serine borate (SB) or 6-diazo-5-oxo-L-norleucine (DON), increased the basal L-Gln release and made it irresponsive to subsequent treatment with TRY. However, the basal release was also increased by superfusion with serine alone or Leu, and this treatment abolished the subsequent effect of TRY as well. Moreover, DON stimulated L-Gln release from capillaries superfused in a standard way, and the effects of DON and TRY were additive. Hence, in the present conditions, SB and DON acted as L-system substrates rather than as GGT inhibitors. Taken together, the results do not support the concept that GGT mediates the Gln-LNAA exchange.

Amino Acids↗

PubMed1986

Chronic metabolic acidosis augments acidification along the inner medullary collecting duct.

The inner medullary collecting duct (IMCD) of the rat is a major site of acidification. However, previous micropuncture studies have failed to demonstrate acidification along the terminal IMCD during chronic acid feeding. To more completely evaluate this question we used the microcatheterization method in rats fed ammonium chloride for 3-7 days. Arterial pH was 7.30 +/- 0.015, and PCO2 was set at 40 +/- 0.6 mmHg. The IMCD data were analyzed as a function of IMCD length between 40% and the tip. Equilibrium pH decreased from 6.21 +/- 0.11 to 5.47 +/- 0.03, whereas PCO2 was unchanged (28 +/- 1 mmHg between the deep samples and tip). Bicarbonate delivery decreased from 92 +/- 14 to 10 +/- 1 nmol/min, titratable acid increased from 462 +/- 33 to 762 +/- 40 nmol/min, and ammonium delivery increased from 2,235 +/- 121 to 3,528 +/- 140 nmol/min. Thus estimated net acid increased from 2,638 +/- 134 to 4,303 +/- 161 nmol/min. To determine whether increasing delivery of buffer to the IMCD would stimulate acid secretion in acute acidosis, rats were studied during the infusion of HCl and creatinine. Arterial pH was 7.18 +/- 0.02. IMCD acidification was not increased compared with our previously published studies during HCl infusion [Am. J. Physiol. 241 (Renal Fluid Electrolyte Physiol. 10): F669-F676, 1981]. We conclude that chronic ammonium chloride ingestion stimulates IMCD acidification and that this increase may be an intrinsic modification of the acidification mechanism of the IMCD.

Acidosis↗

PubMed2003

Effects of different disinfectants on decontamination of laryngoscopes.

Guidelines for controlling possible contamination of laryngoscopes should be formulated with the benefit of relevant experimental data. In this study, the effects of five different disinfectants commonly used for the disinfection of laryngoscopes are evaluated. We formed 14 groups, with 10 blades in each. The first 7 groups were contaminated with hospital related meticillin resistant Staphylococcus aureus (MRSA), and the remaining 7 groups with hospital related multiple resistant Pseudomonas aeruginosa (PA). For the first group of blades, no disinfection procedure was carried out and, were assumed as a control group. Blades in remaining groups were rested for 10 minutes in containers containing 70% alcohol (II), 1/100 dilution of cetrimide (III), 1/100 dilution of chlorhexidine (IV), 1/10 dilution of chlorhexidine (V), 1/10 dilution of povidone iodine (VI), and 1/100 dilution of ammonium chloride (VII). Disinfectant used in a group was considered effective when growth was seen in 5 or less than 5 plates representing that group. All disenfectants tested were found effective on decontamination of laryngoscopes. Five different moderate level disinfectants, which are commonly used for the disinfection of laryngoscopes, have been found effective even on resistant hospital microorganisms like MRSA and P. aeruginosa. They may be the choices of the disinfectants, especially 1/10 dilution of chlorhexidine gluconate and 1/100 dilution of ammonium chloride.

Decontamination↗

PubMed2000

Glutamine synthetase and protease enzyme activities and growth response of ruminal bacterium Prevotella ruminicola strain B(1)4 to nitrogen source and concentration.

The objective of this study was to determine the effects of varying nitrogen sources and concentrations upon glutamine synthetase and protease activities in Prevotella ruminicola strain B(1)4. Based on growth response it appears that ammonium chloride or pepticase limited P. ruminicola becomes nitrogen limited when nitrogen concentration is at 0.5 mM. However, when casein was provided as the sole source of nitrogen P. ruminicola becomes nitrogen limited at 2.5 mM. Glutamine synthetase activity was measured from mid-log phase cells grown in either nitrogen-limited or non-limited conditions. No activity was detectable in the non-limited treatments. However, in the N-limited treatments, pepticase had the highest activity (20.76 units), followed by ammonium chloride (18.72 units) and casein (14.42 units). Protease activity assays indicated that nitrogen-limited cultures had higher proteolytic activity than non-limited cultures. Moreover, these activities appeared to follow the same response pattern as the previously observed glutamine synthetase activities. The results of this study indicate that P. ruminicola strain B(1)4 protease activity may be influenced by nitrogen concentration such that activity increases when nitrogen availability decreases.

Animals↗

PubMed2004

An assessment of sanitation protocols for commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome virus.

The objective of this study was to develop and test a rapid (< 2 h) sanitation protocol designed for porcine reproductive and respiratory syndrome virus (PRRSV) positive commercial transport vehicles involving cold water washing and disinfection via fumigation using scale models of weaned pig trailers. The study consisted of 2 phases. Following experimental contamination of model trailers with PRRSV MN 30-100 (5 x 10(5)TCID50), phase 1 evaluated the presence or absence of PRRSV RNA by polymerase chain reaction (PCR) on swabs collected from the trailer interiors 0, 60, and 90 min after treatment. Phase 2 consisted of evaluating the infectivity of trailers 90 min posttreatment by monitoring changes in the PRRSV-status of naive sentinel pigs housed for 2 h. Treatments included washing only (treatment 1), washing plus formaldehyde fumigation (treatment 2), washing plus fumigation with glutaraldehyde-quaternary ammonium chloride (treatment 3), and washing plus overnight drying (treatment 4). Porcine reproductive and respiratory syndrome virus RNA was detected in all trailers (20 out of 20 replicates) at 60 and 90 min following the application of treatments 1 and 2. These trailers also contained infectious PRRSV, as determined by the infection of naive pigs housed in treated trailers and the testing of organic debris collected from the interior of trailers by swine bioassay. At 90 min posttreatment, all trailers treated with glutaraldehyde-quaternary ammonium chloride were PCR-negative, non-infectious to sentinel pigs, and swine bioassay negative. Similar results were observed in trailers allowed to dry for 8 h. Under the conditions of this study, it appears certain disinfectants may possess different levels of efficacy against PRRSV and PRRSV-positive models may be effectively sanitized in the absence of overnight drying.

Animals↗

PubMed1967

Oxidation of pyrimidine nucleosides and nucleotides by osmium tetroxide.

1. Pyrimidine nucleosides such as thymidine, uridine or cytidine are oxidized readily at 0 degrees by osmium tetroxide in ammonium chloride buffer. There is virtually no oxidation in bicarbonate buffer of similar pH. Oxidation of 1-methyluracil yields 5,6-dihydro-4,5,6-trihydroxy-1-methyl-2-pyrimidone. 2. Osmium tetroxide and ammonia react reversibly in aqueous solution to form a yellow 1:1 complex, probably OsO(3)NH. A second molecule of ammonia must be involved in the oxidation of UMP since the rate of this reaction is approximately proportional to the square of the concentration of unprotonated ammonia. 3. 4-Thiouridine reacts with osmium tetroxide much more rapidly than does uridine. The changes of absorption spectra are different in sodium bicarbonate buffer and in ammonium chloride buffer. They occur faster in the latter buffer and, under suitable conditions, cytidine is a major product. 4. Polyuridylic acid is oxidized readily by ammoniacal osmium tetroxide, but its oxidation is inhibited by polyadenylic acid. Pyrimidines of yeast amino acid-transfer RNA are oxidized more slowly than the corresponding mononucleosides, especially the thymine residues. Appreciable oxidation can occur without change of sedimentation coefficient.

Chromatography↗

PubMed1983

[Structural and functional analysis of the effect of cationic surfactants on Escherichia cells and spheroplasts].

The character of the growth of Escherichia culture after treatment with alkyl dimethylbenzyl ammonium chloride (a cation surface-active substance) has been studied. The action of the preparation at bacteriostatic concentrations is reversible and manifested only by the increased duration of the lag phase. The complete restoration of the processes ensuring the growth and mitosis of the cells usually occurs. The preparation causes disturbances in the permeability barrier of the cell membranes, appearing immediately on contact with cation surface-active substances. This compound affects the cytoplasmic membranes of Escherichia cells at extremely low concentrations (0.0001-0.0002%); as a result, the leakage of low-molecular substances from the cells occurs. These disturbances in permeability are not accompanied by the disappearance of nucleic acids from the cells. The preparation used at bactericidal and subbactericidal concentrations denatures high-molecular cell components to a variable degree. The study of the ultrastructure of cells and spheroblasts shows that alkyl dimethyl-benzyl ammonium chloride destroys the structure of the outer and cytoplasmic membranes, as well as the ribosomal apparatus of Escherichia cells.

Adenosine Triphosphatases↗

PubMed1981

Bacitracin and protease production in relation to sporulation during exponential growth of Bacillus licheniformis on poorly utilized carbon and nitrogen sources.

Growth of Bacillus licheniformis in a chemically defined medium containing glucose and ammonium chloride yielded a doubling time of 1.00 h. Examination of the culture during exponential growth revealed a lack of heat-resistant spores together with a complete absence of detectable concentrations of bacitracin or extracellular serine protease. Replacement of glucose as the sole carbon source by glycerol, pyruvic acid, citric acid, or lactic acid resulted in doubling times of 1.13, 2.00, 3.16, and 3.95 h, respectively. Bacitracin, protease, and heat-resistant spores were produced during exponential growth in amounts related to these doubling times. A qualitatively similar pattern was observed when ammonium chloride was replaced by sodium nitrate, alanine, or glutamic acid which gave doubling times of 1.65, 1.77, and 1.90 h, respectively. Protease, but not bacitracin, concentrations were substantially higher when the growth rate was restricted by use of poor nitrogen rather than poor carbon sources. The relationships between bacitracin production, protease production, and the sporulation process are discussed.

Amino Acids↗

PubMed1995

The regulation of pH in resistance arteries from spontaneously hypertensive and Wistar-Kyoto rats: the effect of bicarbonate.

OBJECTIVE: To assess intracellular pH regulation in the presence of bicarbonate in resistance arteries from spontaneously hypertensive rats and Wistar-Kyoto (WKY) rats. METHODS: Intracellular pH was determined in isolated resistance arteries from male adults SHR and WKY rats with the pH-sensitive fluorescent dye bis-carboxyethyl carboxyfluorescein, while the arteries were mounted in a myograph for simultaneous measurements of force. The arteries were acid-loaded using the ammonium chloride technique and the recovery from the acidosis was determined in resting arteries and in arteries activated with 50 mmol/l potassium or arginine vasopressin. This protocol was performed in the presence and in the absence of bicarbonate. RESULTS: In the absence of bicarbonate the intracellular pH was higher in resting arteries from SHR than in those from WKY rats, whereas during activation no significant difference was found. In the presence of bicarbonate no difference in intracellular pH between arteries from SHR and WKY rats could be found. The addition and washout of 15 mmol/l ammonium chloride were associated with large force transients in activated arteries both from SHR and from WKY rats. The proton recovery rate at intracellular pH 6.85 in the absence of bicarbonate was higher in activated arteries from SHR than in those from WKY rats, whereas in resting arteries no significant difference was found. In the presence of bicarbonate no significant difference between SHR and WKY rat arteries was found. CONCLUSION: In the presence of bicarbonate a possible abnormality of the sodium-hydrogen exchange in resistance arteries from SHR is not manifested, because regulation of intracellular pH by bicarbonate-dependent mechanisms can compensate for such an abnormality.

Animals↗