Effect of bovine serum albumin on the calcium release channel of sarcoplasmic reticulum from rabbit skeletal muscle.
The effect of bovine serum albumin (BSA) on the activity of the calcium release channel of the sarcoplasmic reticulum from rabbit skeletal muscle was investigated using both tension recording from skinned fibres and electrophysiological recording of unitary channel currents from planar lipid membranes. BSA had no effect on the Ca2+ affinity of the contractile proteins, elicited no tension per se in Ca(2+)-loaded skinned fibres, but potentiated caffeine-induced tension. Maximum potentiation was observed with 0.05-0.5% BSA. BSA (0.1%) had no detectable effect on the basal activity of the Ca(2+)-release channel incorporated in lipid bilayer. However, channel stimulation elicited by either caffeine (2 mM) or ATP (60 microM) was further enhanced by BSA (0.1%), as indicated by significant increases in Po, the open probability of the channel. These results suggest that BSA can modulate the response of the skeletal muscle SR Ca(2+)-release channel to different activators such as caffeine and ATP.
Catinot
M P
MP
Laboratoire de Physiologie des Structures Contractiles, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Bastide
B
B
Montel
V
V
Suarez-Kurtz
G
G
Mounier
Y
Y
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects* / Q000648:ultrastructure; D002417:Cattle; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000502:physiology; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D012710:Serum Albumin, Bovine / Q000494:pharmacology*
D015220:Calcium Channels; D010726:Phosphodiesterase Inhibitors; D012710:Serum Albumin, Bovine; D002110:Caffeine; D000255:Adenosine Triphosphate