The effect of ouabain on tension in isolated respiratory tract smooth muscle of humans and other species
| Autor: | Jeffrey S. Fedan, James L. Frost, Pamela Mike, Elliott W. Chideckel |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
Adult
Male medicine.medical_specialty Contraction (grammar) Guinea Pigs Respiratory System chemistry.chemical_element In Vitro Techniques Calcium Ouabain chemistry.chemical_compound Dogs Internal medicine medicine Animals Humans Aged Aged 80 and over Pharmacology Airway Resistance Sodium Middle Aged Atropine Endocrinology chemistry Anesthesia Potassium Trachealis muscle Rabbits medicine.symptom Acetylcholine Histamine Research Article medicine.drug Muscle contraction |
| Zdroj: | British Journal of Pharmacology. 92:609-614 |
| ISSN: | 0007-1188 |
| Popis: | 1. The Na+,K+-pump has been implicated in animal models of airway hyperreactivity. We examined the effects of inhibiting the Na+,K+-pump and Na+,Ca2+-exchange on isometric tone of isolated trachealis from humans and other species. 2. In preparations from 5 out of 9 humans, strong spontaneous contractions (36-48 h-1; up to 1.8 g) developed within 25 min. 3. Ouabain (10(-7)-10(-5) M) caused an immediate and sustained contraction. This response was not blocked by atropine, diphenhydramine, or cimetidine. 4. Contractions were also elicited when the normal physiological solution was changed to a K+-free solution, a procedure which inhibits the Na+,K+-pump, and in reduced (15 mM) Na+ solution, which inhibits Na+,Ca2+ exchange. 5. In preparations of dog and guinea-pig isolated trachea, ouabain (10(-5) M) caused a multiphasic response; in the rabbit, ouabain was without effect. K+-free solution was without effect in the dog preparations and produced relaxation of the guinea-pig trachea. Guinea-pig tracheae responded to a low Na+ solution with a strong contraction. 6. Our findings indicate that: (a) human airway smooth muscle may be a spontaneously contracting muscle, at least in vitro, (b) a prolonged contraction to ouabain is unique for the human airway smooth muscle among the animals tested, as is the contraction in a K+-free medium, and (c) the contractile response does not involve acetylcholine or histamine release, but may involve a Na+,Ca2+-exchange mechanism. These results suggest that the level of Na+,K+-pump activity could play a role in determining the degree of bronchomotor tone in humans. |
| Databáze: | OpenAIRE |
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