The effect of EDTA on contractile responses of guinea-pig trachea in calcium-free medium and on the recovery of the contractile responses in calcium-containing solution.
1. Acetylcholine (0.1 mmol/l) and KCl (80 mmol/l) induce contractile responses in guinea-pig trachea. 2. In the absence of extracellular Ca, contractile responses to ACh or KCl decrease as the preincubation time or the EDTA concentration increases. 3. Exposure of the tissue to Ca-free medium decreases the basal tone. 4. Prolonged incubation in the presence of EDTA (1 mmol/l) promotes a delay in the recovery of the tonic component of the contraction elicited subsequently by acetylcholine and KCl in physiological salt solution, and abolishes the phasic one.
Departamento de Farmacología, Facultad de Farmacia, Universidad de Valencia, Burjassot, Spain.
M A
MA
Noguera
S
S
Chuliá
M P
MP
D'Ocón
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D003470:Culture Media; D003600:Cytosol / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D012996:Solutions; D013997:Time Factors; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D003470:Culture Media; D012996:Solutions; D012965:Sodium Chloride; D011189:Potassium Chloride; D004492:Edetic Acid; D000109:Acetylcholine; D002118:Calcium