Über den Zusammenhang zwischen Membranpotential und Kalium- bzw. Acetylcholin-Kontraktur am chronisch denervierten Rattenzwerchfell
✍ Scribed by Heinz Lüllmann; Edgar Reis
- Publisher
- Springer
- Year
- 1967
- Tongue
- English
- Weight
- 445 KB
- Volume
- 294
- Category
- Article
- ISSN
- 0031-6768
No coin nor oath required. For personal study only.
✦ Synopsis
The influences of potassium ions, of acetylcholine and of carbachol on the membrane potential and on the developing of mechanical tension have been investigated in the chronically denervated rat diaphragm.
-
Contraeture, caused by an increased K + concentration or by acetylcholine diminishes after a few minutes, although the depolarisation then still exists.
-
Potassium ions (140 mE/l) reduce the membrane potential to a level of --15 inV. The maximal depolarisation owing to treatment with acetylcholine or with carbachol was --50 inV. Nevertheless, both types of contracture are identical.
-
After a maximal, earbachol-induced contracture with continuous depolarisation potassium ions are still able to provoke maximal muscle contracture.
-
Slow increase of the potassium concentration up to 140 mMol/1 depolarises the membrane, without giving rise to contracture.
-
No simple relationship exists between the degree of depolarisation and the height of eontracture. For the activation of the contractile system the velocity of the depolarisation seems to be of greater importance.