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PubMed1979

Antibody-dependent cellular cytotoxicity to human colon-tumour cells. I. Lack of tumour specificity in a population study.

The humoral and cellular components of the antibody-dependent cellular cytotoxicity (ADCC) against allogeneic human colonic tumour cell lines were evaluated. The 2 colon cell lines used in this study (HT-29 and ACC-20) were found by immunofluorescence to have carcinoembryonic antigen (CEA) on their surface, and to become sensitive to the lytic effect of unstimulated lymphocytes after coating with heterologous anti-CEA. This reaction was used to evaluate the ADCC activity of mononuclear cells from the peripheral blood of patients with gastrointestinal cancer (mostly local extensive colo-rectal). Remarkable variability was found in the lytic capability (2-50% specific lysis) of both cancer and non-cancer mononuclear cells, with no significant difference between them. Sera from 127 cancer patients and 91 non-cancer patients were tested, using the reaction with heterologous anti-CEA as positive control and as a reference point. In 46 cases (21%) the sera were reactive in this system, and 43 of them were of Blood Group O. However, there was no difference between the cancer patients and the normal controls. The antigenic determinant involved in this reaction is not the Blood Group A specificity but, most probably, a polypeptide common to CEA and A (as shown in the following publication). In addition, trials for the elimination of the non-tumour-specific reaction, by absorption or inhibition, failed to disclose a tumour-specific one. The value of the ADCC assay in monitoring human tumour immunity, and possible ways of eliminating reactivity to normal antigens in this system, are discussed in the light of these findings.

ABO Blood-Group System↗
PubMed2006

Neurologic signs and hyperammonemia in a horse with colic.

A 23-year-old Thoroughbred gelding was referred for the evaluation of acute onset of ataxia and depression, and a 2-day history of fever. On physical examination, the gelding was profoundly depressed and 10-12% dehydrated. The horse appeared very unstable, with a wide-based stance in the hind limbs, severe symmetric ataxia in all 4 limbs, and proprioceptive deficits in both hind limbs. Nasogastric intubation produced 4 L of brown, fetid reflux, and rectal examination revealed mild small intestinal and cecal distention. Hematologic abnormalities included neutropenia with toxic change, compatible with acute inflammation and endotoxemia, and prolonged coagulation times. Serum biochemical abnormalities included prerenal azotemia. metabolic acidosis, and electrolyte abnormalities consistent with enteritis. Blood ammonia concentration was markedly increased (406 micromol/L; reference interval 4-49 micromol/L), however, serum bile acids concentration and hepatic enzyme activities were within reference intervals. Histopathologic examination of a liver biopsy revealed no abnormalities and results of tests for several infectious agents were negative. Clinical signs resolved with correction of the dehydration and electrolyte abnormalities and with antibiotic therapy. The horse was diagnosed with hyperammonemic neuropathy associated with gastrointestinal disease. In such cases, hyperammonemia is caused by increased production of ammonia by organisms in the gastrointestinal tract in combination with increased gut permeability that facilitates ammonia absorption.

Animals↗
PubMed2003

Transdermal delivery of paracetamol for paediatric use: effects of vehicle formulations on the percutaneous penetration.

Paracetamol is a safe and effective analgesic and antipyretic agent, and is one of the most widely used medications for infants and children. The formulations currently available have been designed for oral and rectal administration. However, they are not practical in young patients with vomiting and diarrhoea, or in those who refuse to take the full dose. An alternative route of administration would be a significant contribution to the paediatric pharmacopoeia. The aim of this study was to develop a new transdermal system for optional therapeutic administration of paracetamol in infants and children. In-vivo studies were carried out in animals using a transdermal system of high-loaded, soluble paracetamol in a hydrogel patch, which was also tested in-vitro for 8 h. Although the beneficial contribution of glyceryl oleate to the transdermal penetration of paracetamol seemed to be significant in-vitro, it was shown to be insufficient in-vivo. To improve the penetration of the drug, 4% PEG-40 stearate and 10% ethanol were incorporated as absorption enhancers into the dermal patches. A few hours after application of the improved patches to rats, plasma drug concentrations were elevated to levels comparable with those obtained after oral and subcutaneous administration of a high dose of paracetamol. Since plasma drug concentrations did not reach a constant steady state (as a peak or plateau) during the short-term animal experiments, longer pharmacokinetic studies in conscious animals are necessary.

Acetaminophen↗
PubMed2006

Infrared spectrophotometry of intraluminal meconium calculi in a neonate with imperforate anus and rectourethral fistula.

BACKGROUND/PURPOSE: Intraluminal meconium calculi are a rare cause of neonatal abdominal calcifications in patients with anorectal malformations. To investigate their pathogenesis, we performed infrared spectroscopic analysis of meconium-calcified lesions. METHODS: Meconium calculi were collected from the colostomy in a newborn patient with imperforate anus and rectourethral fistula. The potassium bromide method was employed to obtain the infrared absorption spectrum of the meconium calculi. RESULTS: The wavelength pattern of the meconium calculi exhibited 4 specific peaks at 1570, 1390, 1105, and 1005 cm(-1) between 22% and 45% transmittance values. The unique absorption spectrum exclusively indicated ammonium hydrogen urate (C(5)N(5)O(3)H(7)), having the combined constituents of ammonium and uric acid. CONCLUSIONS: These results suggest that the intraluminal meconium calculi were originally derived from meconium and fetal urine. The stasis of meconium passage and fetal urine mixing through the rectourethral fistula in a low-pH condition was deduced to be the main cause of this rare stone formation.

Anus, Imperforate↗
PubMed1986

Investigation of auranofin-induced diarrhoea.

Gastrointestinal function was assessed in six patients with rheumatoid arthritis who had developed diarrhoea on treatment with Auranofin. With the administration of Auranofin whole gut transit time decreased markedly (to 50% or less of control values) in five of six patients. The speed of passage of intestinal contents through the colon was certainly increased but attempts to assess transit through the upper gastrointestinal tract failed because the breath hydrogen method gave inconclusive results. There was no evidence of colitis and in all cases biopsy of the rectal mucosa appeared normal by light microscopy. In the five patients with rapid intestinal transit faecal weight increased more than two-fold (range +44 to +335%) although in only three cases were the changes sufficient to cause an increased frequency of bowel action. Overall the concentration of sodium in faecal water increased three-fold (mean values rose from 10.6 to 38.3 mmol/l). There were no significant changes in the concentrations of either potassium or chloride but bicarbonate was reduced. Faecal pH fell from a mean value of 7.5 (range 6.8-7.9) to a mean value of 6.4 (range 6.0-7.4). In the three patients who developed overt diarrhoea and in two others taking Auranofin the intestinal uptake of 51Cr-EDTA was increased on average three-fold and there was a similar change in the ratio of the absorption of lactulose/mannitol. The mean clearance of alpha-1-antitrypsin from the circulation into the gastrointestinal tract was doubled. These data indicate an increase in intestinal permeability. In contrast the absorption of vitamin B12 was unaffected and there was no significant change in the excretion of faecal fat although one patient developed mild steatorrhoea. Thus in a selected group of subjects with rheumatoid arthritis the administration of Auranofin caused diarrhoea in association with a reversible defect in intestinal permeability but without significant change in the absorption of nutrients.

Adult↗
PubMed1990

Development of colonic sodium transport in early childhood and its regulation by aldosterone.

Aldosterone is important in the regulation of sodium conservation by both kidney and colon. In the very preterm neonate marked urinary salt wasting occurs because of immature renal tubular function, but little is known of the ontogeny of colonic transport processes. Using an in vivo rectal dialysis technique, we have shown that in the human infant the colon has well developed salt conserving mechanisms from early in the last trimester of gestation and that aldosterone is an important regulatory hormone. Sodium transport mechanisms in the colon appear to develop before those in the kidney and it is possible that the colon is the major organ of sodium conservation in the preterm neonate.

Aldosterone↗
PubMed1997

Effects of different carbohydrate-electrolyte beverages on the appearance of ingested deuterium in body fluids during moderate exercise by humans in the heat.

To determine whether different forms of glucose (free and polymer) associated with sodium chloride influence the rate of water absorption during exercise in the heat, six men took part in five trials. Each trial included a passive heating session which resulted in a 2% loss of body mass, followed by 1h of treadmill exercise (at 50% of maximal oxygen uptake) in warm conditions (dry bulb temperature 35 degrees C, relative humidity 20%-30%). Immediately before exercise, the subjects were given either no fluid or a volume equal to 50% of the fluid previously lost (about 650 ml), chosen from among four D2O-labelled beverages: mineral water, a 6% glucose-electrolyte solution (GS), a 6% maltodextrin solution and a 6% maltodextrin-electrolyte solution. No significant differences were observed among these various beverages so far as temporal accumulation of deuterium in plasma, sweat and urine was concerned. During GS, the plasma volume was completely restored and the drifts of heart rate and rectal temperature were less marked than during other trials. These results would suggest that rehydration with GS was more efficient, probably because of an internal redistribution of water. The proportion of ingested water was twice as high in sweat as it was in urine. These findings may reflect the essential part played by circulatory adjustments in the transfer of plasma water into sweat and urine.

Adult↗
PubMed1985

The influence of body weight on plasma concentration of atropine after rectal administration in children.

To avoid an unpleasant injection, the rectal administration of drugs to children is often to be preferred. Very little has been published on plasma concentrations of atropine given rectally. To determine whether body weight has any influence on the plasma concentrations of atropine, 18 children weighing 7.5-55.0 kg were given 0.02 mg atropine sulphate per kg rectally, and the plasma levels of atropine were determined. The mean peak plasma concentration of atropine was 1.17 ng/ml and it was reached after 33 min. In the group of smaller children (b.w. less than 15 kg) the peak plasma concentration was (0.83 ng/ml) lower than that observed in older children (1.26-1.36 ng/ml), but this difference was not statistically significant. Plasma concentrations in the group of smaller children declined significantly faster than in the other weight groups.

Adolescent↗
PubMed2003

Bioavailability of a morphine suppository is increased after intracolostomal administration in colostoma-constructed rabbits.

This study was performed to assess the pharmacokinetics of morphine and its major metabolites after its rectal or colostomal administration in rectal-resected (ROP) or colostoma-constructed (SOP) rabbits, respectively. The pharmacokinetics of morphine, morphine-3-glucuronide (M3G), and M6G in normal rabbits appeared to be similar to those in human, judging from their plasma concentration-time profiles and the susceptibility of morphine to first-pass metabolism. In SOP, but not ROP, rabbits, the plasma concentrations of morphine, M3G and M6G were significantly increased compared with those in normal rabbits. The AUC of morphine and its metabolites, and the F value of the former in the SOP group were greater than those in the control group, while the elimination half-life (t(1/2)) values were comparable in the two groups. In addition, the disposition of morphine and its metabolites after intravenous (i.v.) administration to SOP rabbits was almost the same as that in normal rabbits, suggesting that an increase in the rate of absorption of morphine in SOP rabbits was not due to inflammation at the absorption site caused by operation, but probably due to its increased solubility in loose stools. Therefore, great attention should be paid when morphine suppositories are intracolostomally administered to colostoma-constructed patients.

Administration, Oral↗
PubMed2006

Influence of pre-, pro-, and synbiotics on the intestinal availability of different B-vitamins.

This study was conducted with 16 male growing pigs (eight pigs with an end-to-end ileo-rectal anastomosis, eight intact pigs) to investigate in metabolic trials the influence of different pre-, pro-, and synbiotics on the precaecal and faecal digestibility of thiamin, riboflavin, pantothenic acid and biotin. A basic experimental diet was supplemented with either pre-, pro-, or synbiotic additives as follows: lactulose (2%), inulin (2%), mannanoligosaccharides (0.3%), Enterococcus faecium DSM 10663 (8 x 10(9) cfu/kg), Enterococcusfaecium DSM 7134 (5 x 10(8) cfu/kg), inulin + Enterococcusfaecium DSM 10663, mannanoligosaccharides + Enterococcus faecium DSM 7134. The precaecal and faecal digestibilities of the investigated B-vitamins were not affected significantly by the administered pre-, pro-, and synbiotics independent of the application period. A higher faecal vitamin excretion vs. the precaecal indicated that thiamin and biotin were synthesized in the colon. On the contrary, for riboflavin and pantothenic acid a higher precaecal vitamin flow compared to the faecal excretion was detected indicating to a certain extent an absorption in the colon.

Anastomosis, Surgical↗
PubMed1978

[Exceptional clinical courses of granulomatous colitis in children and adolescents (author's transl)].

Acute complications are known in chronic ulcerative colitis as well as in Crohn's colitis. They can rarely be seen also in childhood and adolescence. Massive rectal bleeding, particularly acute toxic dilatation of the large bowel should be treated surgically after a short-term medical therapy. The procedure of choice is the one stage proctocolectomy. Alternatively the method described by TURNBULL performing a loop ileostomy and several colostomies can be used. Besides the clinical symptoms and signs more than 8 stools and a temperature of more than 38 degrees C in the first 24 hours of hospitalisation can predict a severe clinical course.

Adolescent↗
PubMedDate not supplied

[Circadian rhythm of blood acetylcholinesterase after administration of organophosphate compounds during hypokinesia].

Circadian and ultradian rhythms of blood acetylcholinesterase (ACE) and rectal temperature were investigated during hypokinesia and administration of a toxic organic phosphate compound in various doses. Hypokinesia was found to produce a strong desynchronizing effect on ACE and thermal regulation. It is maintained that the use of chemicals with a well documented mechanism of action may yield reliable information about biorhythm restructuring in response to exogenous effects. It is emphasized that biorhythm changes should be taken into consideration when arranging work schedules in hypokinetic conditions.

Acetylcholinesterase↗
PubMed1991

Targeting in the gastrointestinal tract: new approaches.

Most drug products are administered via the alimentary canal; prominent are the dosage forms which are swallowed, i.e., p.o. dosage forms, followed by those administered within the oral and the rectal cavities. The innermost surface of the alimentary canal is the epithelial lining which is void of keratinized superficial layers. The epithelium at both ends of the canal, i.e., oral cavity and esophagus, and anal canal is a multilayered (20-50 layers) stratified squamous epithelium, whereas that of the rest of the canal, i.e., gaster, small and large intestine and rectum is a single layer of columnar cells. The drainage is via both venous blood capillaries and lymphatic vessels. Blood drainage from the oral cavity and the lower end of the rectum is directly into systemic circulation via the vena cava. From the GI tract, however, the blood quantitatively passes through the portal vein and liver, hence is available for first-pass effect prior to entering systemic circulation. Targeting can be approached from two angles: 1) to exert the pharmacologic response at a specific site, or 2) to utilize a specific site for drug absorption. Targeting utilizes the anatomic, histologic, physiologic and biochemical features of various segments within the alimentary canal, paired with the design of special drug delivery systems or devices, and the use of special vehicle substances, such as polymers, bioadhesives, sorption promoters, or chemical modification (pro-drug) of the active moiety. Numerous examples of new types of drug delivery systems are presented. Many novel drug delivery systems discussed are still in experimental stage and evaluation, or even in the conceptual stage. However, it is anticipated that they all will contribute to further advancement in optimizing drug therapy.

Animals↗
PubMed1997

Pharmacokinetic considerations of new insulin formulations and routes of administration.

There is a continuing search for improved insulin formulations in order to imitate as closely as possible the physiological pattern of insulin secretion, and thereby to minimise the complications of diabetes mellitus. The major advances achieved to date are in the area of human insulin analogue synthesis resulting from the introduction of recombinant DNA techniques, and in improved delivery systems that utilise noninvasive or minimally invasive modes of administration. To accommodate postprandial hyperglycaemia, monomeric insulin formulations have been developed, of which insulin lispro (the Lys-Pro analogue) is already approved for clinical use. These formulations have a rapid rate of absorption and, therefore, have to be administered at meal time (unlike the previous short-acting formulations). Their residence time is also about 2-fold shorter than regular human insulin; this minimises the risk of the excessive hypoglycaemic effect that characterises regular human insulin formulations. Certain proinsulin formulations with hepatoselective activity have been developed but were found to be poorly tolerated. The newer proinsulin molecules do not show hepato-selective properties. In order to generate basal insulin levels, peakless long-acting formulations have been developed, including: a soluble formulation (which upon subcutaneous administration, produces a 'depot-like' sustained release mechanism), albumin-bound insulin and cobalt-insulin hexamer formulations. To improve patient compliance the 'pen' device was developed for subcutaneous injections. Programmable infusion pumps were developed to avoid repetitive subcutaneous injections. Great efforts have been made in searching for noninvasive modes of insulin administration that will avoid the need for parenteral administration. These include: oral, colonic, rectal, nasal, ocular, buccal, pulmonary, uterine and transdermal routes of administration. Various enhancers have been tested to increase the bioavailability of each route. At present these alternative routes do not provide clinically relevant substitutes for the subcutaneous mode of administration. In conclusion, although the newer formulations provide certain advantages, there is still much to be done to further facilitate and improve insulin therapy.

Amino Acid Sequence↗
PubMed2000

Triptans in migraine: a comparative review of pharmacology, pharmacokinetics and efficacy.

Triptans are a new class of compounds developed for the treatment of migraine attacks. The first of the class, sumatriptan, and the newer triptans (zolmitriptan, naratriptan, rizatriptan, eletriptan, almotriptan and frovatriptan) display high agonist activity at mainly the serotonin 5-HT1B and 5-HT1D receptor subtypes. As expected for a class of compounds developed for affinity at a specific receptor, there are minor pharmacodynamic differences between the triptans. Sumatriptan has a low oral bioavailability (14%) and all the newer triptans have an improved oral bioavailability and for one, risatriptan, the rate of absorption is faster. The half-lives of naratriptan, eletriptan and, in particular, frovatriptan (26 to 30h) are longer than that of sumatriptan (2h). These pharmacokinetic improvements of the newer triptans so far seem to have only resulted in minor differences in their efficacy in migraine. Double-blind, randomised clinical trials (RCTs) comparing the different triptans and triptans with other medication should ideally be the basis for judging their place in migraine therapy. In only 15 of the 83 reported RCTs were 2 triptans compared, and in 11 trials triptans were compared with other drugs. Therefore, in all placebo-controlled randomised clinical trials, the relative efficacy of the triptans was also judged by calculating the therapeutic gain (i.e. percentage response for active minus percentage response for placebo). The mean therapeutic gain with subcutaneous sumatriptan 6mg (51%) was more than that for all other dosage forms of triptans (oral sumatriptan 100mg 32%; oral sumatriptan 50mg 29%: intranasal sumatriptan 20mg 30%; rectal sumatriptan 25mg 31%; oral zolmitriptan 2.5mg 32%; oral rizatriptan 10mg 37%; oral eletriptan 40mg 37%; oral almotriptan 12.5mg 26%). Compared with oral sumatriptan 100mg (32%), the mean therapeutic gain was higher with oral eletriptan 80mg (42%) but lower with oral naratriptan 2.5mg (22%) or oral frovatriptan 2.5mg (16%). The few direct comparative randomised clinical trials with oral triptans reveal the same picture. Recurrence of headache within 24 hours after an initial successful response occurs in 30 to 40% of sumatriptan-treated patients. Apart from naratriptan, which has a tendency towards less recurrence, there appears to be no consistent difference in recurrence rates between the newer triptans and sumatriptan. Rizatriptan with its shorter time to maximum concentration (tmax) tended to produce a quicker onset of headache relief than sumatriptan and zolmitriptan. The place of triptans compared with non-triptan drugs in migraine therapy remains to be established and further RCTs are required.

Animals↗
PubMedDate not supplied

[Chloral hydrate: a hypnotic best forgotten?].

Synthesised by Justin Liebig in 1832 chloral hydrate is one of the oldest synthetic agents. Since 1869 it has been in use for hypnotic or sedative purposes. Chloral hydrate was used a lot from the end of the 19th century to the middle of the 20th century. Since then chloral hydrate has been less frequently in use as a hypnotic. In the 1990's, the principal use of chloral hydrate in pediatrics was the sedation of children for minor surgery during dental or diagnostic procedures. In general practice, it is an analgesia found in topical preparations. It was known as safe and easy to use. Now it is shown to be potentially dangerous (risk of death in case of intoxication) and there is doubt about genotoxicity and carcinogenecity. The pharmacological property was known in 1948 when Butler discovered the principal active metabolite, trichloroethanol. The gastro-intestinal tract rapidly absorbs chloral hydrate after oral or rectal use. The sedative and hypnotic effects appear in 20 to 60 minutes. The main metabolites [trichloroethanol (TCE) and trichloroacetic acid (TCA)] are formed by hepatocytes and erythrocytes. The half-life of chloral hydrate is short (a few minutes), the half lives of the metabolics are longer, 8 to 12 hours for TCE and 67 hours for TCA. The affinity for lipids is high. It is eliminated principally by the kidneys. Its mechanism of action is unknown. It is a depressor of the SNC, and the sedation is attributed to chloral hydrate and the hypnotic effect to TCE. The interactions appear with: alcohol, anticoagulants, amitriptyline and furosemide. The use of flumazenil (a gaba antagonist), in case of intoxication, indicates a possible action of GABA. The posology is usually between 0.5 to 2 g per day. Chloral hydrate is taken during meals to prevent gastric irritation. The main side effects are digestive, cardiologic (risk of rhythm disorder), dermatologic, neuropsychiatric (withdrawn, delusions, hallucination, dependence) and ophthalmologic. Death occurs after absorption of doses of around 10 g of hydrate chloral, some cases were reported with 5 g. The use of hydrate chloral is contra-indicated in cases of gastric ulcers, hepatic insufficiency, porphyry, respiratory insufficiency, association with anticoagulants and hyper sensibility. Nowadays should we be using chloral hydrate in cases of insomnia in adult and older people? A recent preclinical working group of the French Agency for evaluation of medicinal products reassessed the benefit/risk ratio of chloral hydrate. Many references are found about genotoxicity and carcinogenicity in recent literature. In France, since the end of 2000, chloral hydrate has been withdrawn from many medications for external use in dermatology and in stomatology. Chloral hydrate can be used as a pediatric sedative only once in a lifetime. The psychiatric indication for insomnia is no longer justified and especially in older people.

Adult↗
PubMed2003

Rectal tissue, plasma and urine concentrations of mesalazine after single and multiple administrations of 500 mg suppositories to healthy volunteers and ulcerative proctitis patients.

OBJECTIVE: Patients with ulcerative proctitis may have rectal mucosal properties different from healthy volunteers. This project compared the pharmacokinetics of rectally administered mesalazine in these two populations. METHODS: In two separate studies, nine patients with ulcerative proctitis and 16 healthy volunteers received a single 500 mg mesalazine suppository and then 500 mg every 8 h for 5 days. Blood samples were collected for 12 h in healthy volunteers and 30 h in patients, and urine for 24 h in healthy volunteers and 30 h in patients. Rectal biopsies were performed 8 h after the last dose. RESULTS: After a single dose to patients, mean mesalazine half-life (s.d.) was 5.0 (3.6) h. At steady-state, means (s.d.) were 89.1 (78.9) ng/mL for C(min), 361.1 (240.8) ng/mL for C(max), and 7.1 (7.3) h for half-life. Mean (range) rectal mesalazine concentrations were 167 (1.4-541.6) ng/mg tissue. After a single dose in healthy volunteers, mean (s.d.) half-life was 4.0 (4.7) h. At steady-state, means (s.d.) were 22.4 (61.6) ng/mL for C(min), 359.4 (166.3) ng/mL for C(max), and 0.9 (0.5) h for half-life. CONCLUSION: Mesalazine is released in the rectum of patients, with a bioavailability of about 40%. Tissue distribution is also appreciable. Both parameters appear higher than in healthy volunteers.

Adult↗
PubMed1978

The presence of two (Na+ + K+)-ATPase inhibitors in equine muscle ATP: vanadate nad a dithioerythritol-dependent inhibitor.

A potent inhibitor of (Na+ + K+)-ATPase activity was purified from Sigma equine muscle ATP by cation- and anion-exchange chromatography. The isolated inhibitor was identified by atomic absorption spectroscopy and proton resonance spectroscopy to be an inorganic vanadate. The isolated vanadate and a solution of V2O5 inhibit sarcolemma (Na+ + K+)-ATPase with an I50 of 1 micrometer in the presence of 1 mM ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA), 145 mM NaCl, 6mM MgCl2, 15 mM KCl and 2 mM synthetic ATP. The potency of the isolated vanadate is increased by free Mg2+. The inhibition is half maximally reversed by 250 micrometer epinephrine. Equine muscle ATP was also found to contain a second (Na+ + K+)-ATPase inhibitor which depends on the sulfhydryl-reducing agent dithioerythritol for inhibition. This unknown inhibitor does not depend on free Mg2+ and is half maximally reversed by 2 micrometer epinephrine. Prolonged storage or freeze-thawing of enzyme preparations decreases the susceptibility of the (Na+ + K+)-ATPase to this inhibitor. The adrenergic blocking agents, propranolol and phentolamine, do not block the catecholamine reactivation. The inhibitors in equine muscle ATP also inhibit highly purified (Na+ + K+)-ATPase from shark rectal gland and eel electroplax. The inhibitors in equine muscle ATP have no effect on the other sarcolemmal ATPases, Mg2+-ATPase, Ca2+-ATPase and (Ca2+ + Mg2+)-ATPase.

Adenosine Triphosphatases↗