Abstract
Intact muscle fibres from Balanus nubilus develop tensions of up to 600 kN sd m-2 during electrical stimulation. The rise of tension occurs with a half-time (177 ms at 12° C) about fivefold longer than that of tetanised frog muscle at the same temperature. The response of myofibrillar bundles to a rapid stretch resembles that of frog muscle but has a yo value (i.e. the size of an instantaneous release necessary to just discharge tension) which is ca. 2.5 times smaller, and phase 2 of the tension transient (the "quick phase") occurs at a rate comparable to that of frog muscle. In contrast, the ATPase activity (0.018 mmoles · kg wet weight-1 · s-1) of this preparation and its maximum shortening velocity (0.15-0.16 muscle lengths · s-1) are both at least fivefold slower than frog muscle. These findings can be accounted for by a cross-bridge cycle in barnacle muscle in which events prior and subsequent to the tension generating step(s) occur at a rate at least fivefold slower than comparable steps in frog muscle, but the step(s) associated with tension development occur at similar rates in the two preparations. Since the rate of mechanical relaxation in barnacle muscle is modified in the presence of intracellular calcium buffers and by depolarisation-induced elevation of the free calcium during the relaxation phase, it is proposed that the time course of relaxation is not determined exclusively by the kinetics of the cross-bridge cycle, but is also dependent on the free calcium concentration during relaxation.
| Original language | English |
|---|---|
| Pages (from-to) | 554-565 |
| Number of pages | 12 |
| Journal | Pflügers Archiv |
| Volume | 415 |
| Issue number | 5 |
| DOIs | |
| State | Published - Feb 1 1990 |
| Externally published | Yes |
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Keywords
- Aequorin
- Barnacle
- Calcium
- Mechanics
ASJC Scopus subject areas
- Physiology (medical)
- Physiology
- Clinical Biochemistry
Cite this
Mechanical characteristics of skinned and intact muscle fibres from the giant barnacle, Balanus nubilus. / Griffiths, P. J.; Duchateau, J. J.; Maeda, Y.; Potter, J. D.; Ashley, C. C.
In: Pflügers Archiv, Vol. 415, No. 5, 01.02.1990, p. 554-565.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanical characteristics of skinned and intact muscle fibres from the giant barnacle, Balanus nubilus
AU - Griffiths, P. J.
AU - Duchateau, J. J.
AU - Maeda, Y.
AU - Potter, J. D.
AU - Ashley, C. C.
PY - 1990/2/1
Y1 - 1990/2/1
N2 - Intact muscle fibres from Balanus nubilus develop tensions of up to 600 kN sd m-2 during electrical stimulation. The rise of tension occurs with a half-time (177 ms at 12° C) about fivefold longer than that of tetanised frog muscle at the same temperature. The response of myofibrillar bundles to a rapid stretch resembles that of frog muscle but has a yo value (i.e. the size of an instantaneous release necessary to just discharge tension) which is ca. 2.5 times smaller, and phase 2 of the tension transient (the "quick phase") occurs at a rate comparable to that of frog muscle. In contrast, the ATPase activity (0.018 mmoles · kg wet weight-1 · s-1) of this preparation and its maximum shortening velocity (0.15-0.16 muscle lengths · s-1) are both at least fivefold slower than frog muscle. These findings can be accounted for by a cross-bridge cycle in barnacle muscle in which events prior and subsequent to the tension generating step(s) occur at a rate at least fivefold slower than comparable steps in frog muscle, but the step(s) associated with tension development occur at similar rates in the two preparations. Since the rate of mechanical relaxation in barnacle muscle is modified in the presence of intracellular calcium buffers and by depolarisation-induced elevation of the free calcium during the relaxation phase, it is proposed that the time course of relaxation is not determined exclusively by the kinetics of the cross-bridge cycle, but is also dependent on the free calcium concentration during relaxation.
AB - Intact muscle fibres from Balanus nubilus develop tensions of up to 600 kN sd m-2 during electrical stimulation. The rise of tension occurs with a half-time (177 ms at 12° C) about fivefold longer than that of tetanised frog muscle at the same temperature. The response of myofibrillar bundles to a rapid stretch resembles that of frog muscle but has a yo value (i.e. the size of an instantaneous release necessary to just discharge tension) which is ca. 2.5 times smaller, and phase 2 of the tension transient (the "quick phase") occurs at a rate comparable to that of frog muscle. In contrast, the ATPase activity (0.018 mmoles · kg wet weight-1 · s-1) of this preparation and its maximum shortening velocity (0.15-0.16 muscle lengths · s-1) are both at least fivefold slower than frog muscle. These findings can be accounted for by a cross-bridge cycle in barnacle muscle in which events prior and subsequent to the tension generating step(s) occur at a rate at least fivefold slower than comparable steps in frog muscle, but the step(s) associated with tension development occur at similar rates in the two preparations. Since the rate of mechanical relaxation in barnacle muscle is modified in the presence of intracellular calcium buffers and by depolarisation-induced elevation of the free calcium during the relaxation phase, it is proposed that the time course of relaxation is not determined exclusively by the kinetics of the cross-bridge cycle, but is also dependent on the free calcium concentration during relaxation.
KW - Aequorin
KW - Barnacle
KW - Calcium
KW - Mechanics
UR - http://www.scopus.com/inward/record.url?scp=0025373717&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025373717&partnerID=8YFLogxK
U2 - 10.1007/BF02583506
DO - 10.1007/BF02583506
M3 - Article
C2 - 2139207
AN - SCOPUS:0025373717
VL - 415
SP - 554
EP - 565
JO - Pflugers Archiv European Journal of Physiology
JF - Pflugers Archiv European Journal of Physiology
SN - 0031-6768
IS - 5
ER -