Alpha-adrenergic receptors in XXXX skeletal muscle.

@entity3160 @entity62082 @entity35 @entity26 @entity5521 @entity9006 @entity2647 @entity3159 @entity413
Sarcolemma-enriched preparations from muscles rich in slow oxidative red fibres contained specific binding sites for the alpha 1 antagonist, @entity3159 (e.g. soleus Kd 0.13 nM, Bmax 29 fmol/mg protein). Binding sites for @entity3159 were almost absent from white muscle. Displacement of @entity3159 binding from sarcolemma of soleus muscle ( @entity5521 greater than @entity2647 greater than idazoxan greater than @entity3160 ) suggested that the receptors were alpha 1. Binding sites for @entity62082 (beta antagonist) were also more concentrated on red than white muscle and outnumbered @entity3159 sites by approx. 10:1. Binding sites for @entity9006 (alpha 2 antagonist) were undetectable. Contamination of sarcolemma-enriched preparations by endothelial tissue indicated by the activity of angiotensin converting enzyme did not correlate with @entity3159 binding. It is concluded that post-synaptic alpha 1 adrenergic receptors are present on the sarcolemma of slow oxidative red fibres of @entity35 skeletal muscle. The presence provides the mechanistic basis for apparent alpha-adrenergic effects to increase @entity413 and @entity26 uptake in perfused @entity35 hindquarter.
