Active sodium-potassium transports in skeletal muscles of deoxycorticosterone hypertensive rats

CNS-induced suppressions of active Na⁺,K⁺ transport was investigated in both 'tonic' muscle, soleus (SOL), and 'twitch' muscle, extensor digitorum longus (EDL) of deoxycorticosterone acetate (DOCA) hypertensive rats. There was a marked K⁺ loss and Na⁺ accumulation in the skeletal and smooth muscles of DOCA hypertensive rats. The cellular K⁺ loss was in the order of SOL > EDL > diaphragm > intestine > aorta. However, liver, kidney and CNS organs such as cerebrum, cerebellum and medulla oblongata were spared from this K⁺ fall. Sciatic nerve sectioning or cervical transection activated the active Na⁺, K⁺ transport in SOL during DOCA hypertension but inhibited further the pump activity in EDL. The application of tetrodotoxin on the sciatic nerve also activated the Na⁺, K⁺ transport in SOL but inhibited the transport in EDL. The facilitatory effect of denervation on the pump activity in SOL was abolished by pretreatment with ouabain. Injection of curare had no effect on Na⁺ and K⁺ contents in both SOL and EDL. These results indicate that the CNS is involved differently on the neural regulations of the active Na⁺, K⁺ transport systems in SOL and EDL of DOCA hypertensive rats.