The effect of Ba2+ on the nitrergic mechanism in the isolated frog lung preparation.
1. The present study was undertaken to investigate effects of Ba2+ on the isolated frog lung strips depolarized by 20 mM K+ in Ca2+ free Ringer solution. 2. Ba2+ produced monophasic relaxant response, whereas Ca2+ induced biphasic response consisting of a transient relaxation and a marked contraction. Both kinds of relaxation were inhibited completely by L-NOARG. L-arginine reversed the action of L-NOARG. 3. Ferrous sulfate, pyrogallol, hydroquinone, and vanadate reduced the Ba(2+)-induced relaxation in a concentration-dependent manner. 4. These findings suggest that Ba(+)-induced relaxation may fully be mediated by the nitrergic mechanism and the effect of Ba2+ on the nitric oxide synthase may be more selective than Ca2+.
Karatas
Y
Y
Cukurova University, Faculty of Medicine, Department of Pharmacology, Balcali Adana, Turkey.
Atçi
S
S
Uçar
P
P
Dikmen
A
A
Singirik
E
E
Baysal
F
F
D000818:Animals; D001464:Barium / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D005260:Female; D005290:Ferric Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011894:Rana pipiens
D005290:Ferric Compounds; D001464:Barium; C024823:ferric sulfate; D019001:Nitric Oxide Synthase; D002122:Calcium Chloride