Mp. Catinot et al., EFFECT OF BOVINE SERUM-ALBUMIN ON THE CALCIUM-RELEASE CHANNEL OF SARCOPLASMIC-RETICULUM FROM RABBIT SKELETAL-MUSCLE, Acta Physiologica Scandinavica, 160(3), 1997, pp. 199-205
The effect of bovine serum albumin (BSA) on the activity of the calciu
m release channel of the sarcoplasmic reticulum from rabbit skeletal m
uscle was investigated using both tension recording from skinned fibre
s 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 Ca2+-loaded skinne
d fibres, but potentiated caffeine-induced tension. Maximum potentiati
on was observed with 0.05-0.5% BSA, BSA (0.1%) had no detectable effec
t on the basal activity of the Ca2+-release channel incorporated in li
pid bilayer. However, channel stimulation elicited by either caffeine
(2 mM) or ATP (60 mu M) was further enhanced by BSA (0.1%), as indicat
ed by significant increases in P-o, the open probability of the channe
l. These results suggest that BSA can modulate the response of the ske
letal muscle SR Ca2+-release channel to different activators such as c
affeine and ATP.