Barium: A Magician for Smooth Muscles

ByОлена Коновалова

         Barium (Ba)

         Magician and wizard for smooth muscles
          
    Barium belongs to toxic trace elements and is not classified among essential (vital) or conditionally essential trace elements. In the human body, it has a pronounced effect on smooth muscles.   

 
     The daily requirement for barium in the human body has not been established; the average daily intake is in the range of 0.3–1 mg.
 
     The barium content in the body of an adult human is about 20 mg.
 
    The absorption of soluble barium salts in the gastrointestinal tract is about 10%, and sometimes this figure reaches 30%. In the respiratory tract, absorption can reach 60–80%. The barium content in blood plasma changes along with changes in calcium concentration.
 

    Barium is present in small amounts in all organs and tissues, but it is most concentrated in the brain, muscles, spleen, and lens of the eye (it is found in all membranes and media of the eye). About 90% of the total barium in the body is concentrated in bones and teeth.
    Organs rich in calcium also contain high levels of barium. When the parathyroid gland is removed, the levels of calcium and barium in the blood serum decrease.

 

    Biological role in the human body. Even in negligible concentrations, barium has a pronounced effect on smooth muscles (relaxes them at low concentrations, causes contraction at higher levels.)

     This is primarily related to the stimulation of acetylcholine release by large doses of barium, thereby enhancing muscle contractions, intestinal peristalsis, arterial hypertension, muscle fibrillation, and disturbances in cardiac conduction.
 
    The absorption of barium from the gastrointestinal tract depends on the solubility of its compounds, which, except for barium sulfate, increases with decreasing pH. When barium compounds enter the lungs as dust or aerosol, they penetrate well through the basement membrane. Poorly soluble compounds can accumulate in the lungs.
 
    Barium compounds reduce the permeability of potassium channels. The level of extracellular potassium decreases, while intracellular potassium increases. Under the influence of barium, depolarization of cell membranes is observed, followed by pronounced hypokalemia, decreased membrane potentials, and failure of membrane repolarization. Barium stimulates insulin secretion, leading to hypoglycemia. The level of adrenaline in the blood increases. Capillary permeability increases, which may be accompanied by hemorrhages and edema.
 
    It has been established that in ischemic heart disease, chronic coronary insufficiency, and diseases of the digestive organs, the barium content in tissues decreases.
 

    Synergists and antagonists of barium. Barium is similar in its properties to calcium, which is mainly found in bone tissue, so barium ions can replace calcium in bones. This can result in both synergism and antagonism.

 

    Signs of barium deficiency. There is no reliable data on clinical manifestations caused by barium deficiency.

 

    Barium is classified as toxic trace elements, however, this element is not considered mutagenic or carcinogenic.
    All barium compounds are toxic (except for barium sulfate, which is used in radiology).

    Barium compounds are used in various sectors of the economy. Soluble (barium chloride, barium carbonate, barium nitrate, barium hydroxide) and insoluble (barium sulfate) compounds are distinguished.
 

    Soluble barium compounds are highly toxic, used as rodenticides; barium sulfate is non-toxic and used in radiology.
    LD50 of barium chloride for rats upon intravenous administration is 7.9 mg/kg; for mice upon intraperitoneal administration – 54 mg/kg, the lethal dose for large animals is 15-30 g, for pigs and sheep – 5-15 g, for humans – 0.8-3.5 g (11.4 mg/kg) upon oral intake.
    LD50 of barium carbonate is 57 mg/kg.
    Barium has neurotoxic, cardiotoxic, and hemotoxic effects.

    The symptoms of barium poisoning in various animal species are mostly similar. Hypertension, premature ventricular contractions, ventricular tachycardia, ventricular fibrillation, and asystole. Eye discharge, mydriasis, salivation, nausea, vomiting are observed. Abdominal wall tenderness, diarrhea, swallowing difficulties. Muscle fibrillations, rapid breathing, pulmonary edema, tonic, clonic seizures, and paralysis. Hypokalemia and hypophosphatemia, metabolic acidosis, and hypoglycemia.

 

    The main manifestations of barium excess: muscle spasms, coordination disorders, and brain activity disturbances; excessive salivation, nausea, vomiting, colic, diarrhea, dizziness, tinnitus, pallor of the skin, profuse cold sweat; weak pulse, bradycardia, extrasystole.

 

    Treatment of barium poisoning. The stomach is washed out with a 1% solution of sodium or magnesium sulfate, followed by the administration of saline laxatives. A 10% solution of sodium sulfate is administered intravenously at a dose of 0.2 ml/kg (0.02 g/kg), every 15 minutes until the clinical signs of poisoning disappear. However, this may lead to acute renal failure due to the precipitation of barium sulfate in the kidneys. To prevent possible complications, diuresis is forced: saline plasma substitutes are administered intravenously at a dose of 20 ml/kg, followed by furosemide at a dose of 0.001-0.01 g/kg. Tetracycline-calcium, 40% glucose solution, isotonic sodium chloride solution are prescribed. In case of bradycardia: atropine sulfate intravenously with glucose. In case of heart rhythm disturbances, potassium chloride is administered intravenously as a 0.5% solution in a 10% glucose solution at a rate of 40.0 ml/min, at a dose of 1g/13.4-26.8kg, with repeat administration if necessary. Cordiamin, sodium benzoate caffeine, vitamins B1 and B6, antihistamines, analgesics, and antispasmodics are prescribed. To prevent the worsening of rhythm and conduction disturbances in the heart: glucocorticoids and vitamin E. Calcium preparations and cardiac glycosides are contraindicated.

 

    Barium is necessary: in ischemic heart disease, chronic coronary insufficiency, and diseases of the digestive organs.
    Additionally, barium exerts a consolidating effect on tissues, and this effect is used for the treatment of hypertrophied glands. Homeopaths recommend taking barium carbonate for elderly people suffering from obesity, when symptoms of cerebral vessel sclerosis are present, as well as in some cardiovascular diseases (hypertension, aortitis, aneurysms), respiratory diseases (adenoids, chronic tonsillitis, bronchitis, recurrent angina), and gastrointestinal tract diseases (gastritis, meteorism, diarrhea, constipation).

 

    Dietary sources of barium: some marine organisms can accumulate barium from the surrounding water, in concentrations 7–100 (and for some marine plants – up to 1000) times higher than its content in seawater.
    Some plants (Brazil nut, soybeans, and tomatoes, for example) can also accumulate barium from the soil. However, in areas where the concentration of barium in water is high, drinking water may also contribute to the total barium intake.

 

 

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