Contractile effects of vanadate on monkey and rabbit tracheal smooth muscle.
The effects of vanadate (Na3VO4: VAN) on isolated tracheal smooth muscle of monkey (Macaca fascicularis) and rabbit were examined. VAN (10(-5)-10(-3) M) induced a sustained contraction in both tracheae which was not affected by atropine, tetrodotoxin or tripelennamine. Indomethacin potentiated VAN-induced contraction in monkey trachea but had no effect in rabbit trachea. In Ca-free solution, high K was ineffective whereas VAN or carbachol induced a small transient contraction. In both tracheae, the K-induced contraction was completely inhibited by verapamil while the VAN- and carbachol-induced contractions were partially inhibited by this inhibitor. Sodium nitroprusside was ineffective in rabbit trachea. In monkey trachea, however, K-induced contraction was completely inhibited and VAN- and carbachol-induced contractions were partially inhibited by sodium nitroprusside. Readmission of 5.4 mM K transiently relaxed the carbachol-induced contraction in trachea pretreated with a K-free solution. Ouabain completely and VAN partially inhibited this K-induced relaxation. VAN slightly increased the cellular Na content in rabbit trachea but not in monkey trachea. Previous inhibition of the Na pump activity by a K-free solution containing ouabain did not inhibit the VAN-induced contraction. It is concluded that VAN induces a transient, followed by a sustained contraction in both monkey and rabbit tracheae. The former contraction may be due to a release of cellular Ca and the latter to an influx of external Ca. VAN-induced contractions do not seem to be due to an inhibition of the Na pump activity.
Ueda
F
F
Karaki
H
H
Urakawa
N
N
D000818:Animals; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D008252:Macaca fascicularis; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D011817:Rabbits; D013045:Species Specificity; D014132:Trachea / Q000187:drug effects; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D007473:Ion Channels; D009467:Neuromuscular Depolarizing Agents; D014639:Vanadium; D014638:Vanadates; D006632:Histamine; D002217:Carbachol; D002118:Calcium