Relationship between vanadate induced relaxation and vanadium content in guinea pig taenia coli.
Abstract: Vanadate has been known to induce a transient increase in high K+ induced contraction, and also gradually relax the high K+ contraction itself in guinea pig taenia coli. The relationship between the rate of relaxation and ion content of Na+, K+, and V ion at the cellular level was investigated when vanadate was applied to contracted muscle. Tissue Na+ and V ion content increased linearly, depending on the time after vanadate treatment, reaching maximum levels of approximately 50 mM x kg(-1) and 0.25 mM x kg(-1) wet weight, respectively. There was a positive correlation between the V ion and Na+ contents, while there was a negative correlation between both ions and the relaxed rate of the high K+ induced contraction. The uptake of V ion was affected by the external K+ concentration, and the maximum rate of V ion uptake decreased to 40% in the presence of 90 mM external K+. These results suggest that a small amount of V ion was enough to inhibit the Na+ pump activity and muscle contraction in the high K+ solution.
Mochizuki
M
M
Department of Veterinary Public Health, Nippon Veterinary and Animal Science University, Musashino, Tokyo, Japan. nvau-vph@interlink.or.jp
Ueda
F
F
Sano
T
T
Hondo
R
R
D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000378:metabolism*; D004566:Electrodes; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology*; D014639:Vanadium / Q000378:metabolism*
D014639:Vanadium; D014638:Vanadates; D012964:Sodium; D011188:Potassium