The influence of felodipine and diethyl-stilboestrol on [3H]noradrenaline release in the rat trachea.
The fractional release of [3H]noradrenaline was measured in rings from the rat trachea. Transmitter release was induced either by isotonic KCl (124 mM) or by 2.5 mM Ca added to a Ca-free depolarizing solution. Felodipine, a Ca antagonist (10(-4)M), had no effect on the basal release of [3H]NA whereas it reduced the overflow of transmitter caused by KCl or Ca. Diethyl-stilboestrol (25 microM), which also inhibits Ca influx in smooth muscle, had a stronger inhibitory effect than felodipine on [3H]NA release induced by high K and addition of Ca. Basal efflux of [3H]NA was increased by diethyl-stilboestrol. This increase also occurred in the absence of extracellular Ca.
D000818:Animals; D002118:Calcium / Q000502:physiology; D003470:Culture Media; D004054:Diethylstilbestrol / Q000494:pharmacology*; D015736:Felodipine; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014132:Trachea / Q000378:metabolism*
D003470:Culture Media; D011189:Potassium Chloride; D004054:Diethylstilbestrol; D009543:Nifedipine; D015736:Felodipine; D002118:Calcium; D009638:Norepinephrine