Bovine serum albumin potentiates caffeine- or ATP-induced tension in human skinned skeletal muscle fibers
Human skinned muscle fibers were used to investigate the effects of bovine serum albumin (BSA) on the tension/pCa relationship and on the functional properties of the Ca2+-release channel of the sarcoplasmic reticulum (SR). In both fast- and slow-type fibers, identified by their tension response to...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Associação Brasileira de Divulgação Científica
1997-05-01
|
| Series: | Brazilian Journal of Medical and Biological Research |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000500017 |
| Summary: | Human skinned muscle fibers were used to investigate the effects of bovine serum albumin (BSA) on the tension/pCa relationship and on the functional properties of the Ca2+-release channel of the sarcoplasmic reticulum (SR). In both fast- and slow-type fibers, identified by their tension response to pSr 5.0, BSA (0.7-15 µM) had no effect on the Ca2+ affinity of the contractile proteins and elicited no tension per se in Ca2+-loaded fibers. In contrast, BSA (>1.0 µM) potentiated the caffeine-induced tension in Ca2+-loaded fibers, this effect being more intense in slow-type fibers. Thus, BSA reduced the threshold caffeine concentration required for eliciting detectable tension, and increased the amplitude, the rate of rise and the area under the curve of caffeine-induced tension. BSA also potentiated the tension elicited in Ca2+-loaded fibers by low-Mgv solutions containing 1.0 mM free ATP. These results suggest that BSA modulates the response of the human skeletal muscle SR Ca2+-release channel to activators such as caffeine and ATP. |
|---|---|
| ISSN: | 0100-879X 1414-431X |