title: Effects of nerve cross-union on rat intracellular potassium in fast-twitch and slow-twitch rat muscles.
abstract: 1. Electrolytes of normal, self-innervated and cross-innervated extensor digitorum longus and soleus muscles of rats have been determined.2. [K](i) was 173 m-equiv/l. for both normal and self-innervated extensor digitorum longus. In cross-innervated extensor digitorum longus it was reduced to 159 m-equiv/l.3. For normal and self-innervated soleus, [K](i) was 150 m-equiv/l. and 154 m-equiv/l. respectively. In cross-innervated soleus it was increased to 182 m-equiv/l.4. The content and distribution of most other electrolytes of cross-innervated soleus, as well as its weight, were not significantly different from those of controls. On the other hand, cross-innervated extensor digitorum longus weighed about half as much as controls and contained markedly elevated Na(+), Cl(-) and extrafibre water and reduced non-collagenous protein and intrafibre water.5. It is concluded that [K](i) of fast-twitch and slow-twitch muscle fibres are under neural regulation. Possible mechanisms for this regulation are discussed.
mesh_terms: D000818:Animals; D002712:Chlorides / Q000032:analysis; D006614:Hindlimb; D008297:Male; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000032:analysis; D009132:Muscles / Q000032:analysis / Q000294:innervation* / Q000378:metabolism; D009416:Nerve Regeneration; D009929:Organ Size; D011188:Potassium / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000032:analysis; D013997:Time Factors; D014867:Water / Q000032:analysis
chemical_list: D002712:Chlorides; D009124:Muscle Proteins; D014867:Water; D012964:Sodium; D011188:Potassium