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Dissociation betwee...
Dissociation between force and [Ca2+]i during extra systoles in guinea-pig ventricular muscle microinjected with fura-2
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- Arheden, Håkan (författare)
- Lund University,Lunds universitet,Klinisk fysiologi, Lund,Sektion V,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,Clinical Physiology (Lund),Section V,Department of Clinical Sciences, Lund,Faculty of Medicine
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- Hellstrand, Per (författare)
- Lund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups
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- Wohlfart, Björn (författare)
- Lund University,Lunds universitet,Klinisk fysiologi, Lund,Sektion V,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,Clinical Physiology (Lund),Section V,Department of Clinical Sciences, Lund,Faculty of Medicine
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(creator_code:org_t)
- 2001-12-24
- 1999
- Engelska.
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772. ; 165:1, s. 1-8
- Relaterad länk:
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Abstract
Ämnesord
Stäng
- Thin trabeculae were dissected from the right ventricle of guinea-pig heart and stimulated to contract isometrically at 0.5 Hz (26 degrees C). Rapid and transient changes of force were obtained by inducing three extra systoles (ES1-3) at 450-ms intervals. The two regular contractions (P1-2) following (ES1-3) were potentiated. Fura-2 salt was microinjected into the preparation to monitor intracellular calcium ([Ca2+]i). Three distinct phases of [Ca2+]i were seen: (1) a rapid rising phase to about 200 nmol L(-1), (2) a slower rising phase to a peak at 400 nmol L(-1), and (3) a slow decline to about 50 nmol L(-1). During ES1, there was a discrepancy between force, which decreased, and peak [Ca2+]i, which increased to 600 nmol L(-1). It is likely that the increased [Ca2+]i during the extra systoles reflects increased sarcolemmal calcium inflow, causing post-extra-systolic potentiation. Ryanodine (1-2 microM) was added to inhibit the intracellular calcium release and thus reduce the intracellular [Ca2+]i gradients following excitation. Ryanodine inhibited phase 1 of [Ca2+]i and abolished post-extra-systolic potentiation. There was a close relationship between dF/dt and [Ca2+]i with ryanodine during control and ES1-3. It is likely that fura-2 reports a spatially averaged [Ca2+]i and that phase 1 of the signal therefore apparently underestimates activator calcium in the close vicinity of the contractile elements.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Lungmedicin och allergi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Respiratory Medicine and Allergy (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Kardiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Cardiac and Cardiovascular Systems (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Physiology (hsv//eng)
Nyckelord
- excitation-contraction coupling
- calcium
- fura-2
- force-interval relationships
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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