The K+-sensitive hyperpolarization of rat skeletal muscle and metabolic inhibitors.
The electrogenic contribution of Na-pump to the resting potential was investigated in isolated "Na-rich" rat soleus muscles exposed to K-free medium for more than 4 hr at 37 degree C. When the resting potentials of fibres fell to around - 75 mV in the K-free medium, the addition of K+ to the bathing medium evoked a transient hyperpolarization. The K+-sensitive hyperpolarization was reproducible in repeated K+ challenged at 45 or 60 min cycles. The K+-sensitive hyperpolarization was completely abolished by cooling, by adding ouabain, or by substituting Li+ for Na+, and reduced by low and high pH. DNP and hypoxia had little effect on the K+-sensitive hyperpolarizations.
D019297:2,4-Dinitrophenol; D000818:Animals; D000963:Antimetabolites / Q000502:physiology*; D004140:Dinitrophenols / Q000494:pharmacology; D005121:Extremities / Q000033:anatomy & histology; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000503:physiopathology; D008094:Lithium / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009132:Muscles / Q000502:physiology*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000502:physiology; D013696:Temperature
D000963:Antimetabolites; D004140:Dinitrophenols; D010042:Ouabain; D008094:Lithium; D012964:Sodium; D019297:2,4-Dinitrophenol; D011188:Potassium