Abstract
We have incorporated the myosin fragment heavy meromyosin (HMM), which is known to interact mechanochemically and enzymatically with actin filaments, into intact chromaffin cells of the bovine adrenal medulla, in order to study the possible involvement of actin and myosin in stimulus-secretion coupling. HMM was found to stimulate secretion of catecholamines, to cause depolarization of the plasma membrane, and to enhance 22Na+ uptake. HMM-stimulated catecholamine secretion was dependent on the presence of extracellular Na+. The Na+ uptake caused by HMM was inhibited by 10 μM amiloride. Acetylcholine-stimulated catecholamine secretion and 22Na+ uptake were both enhanced by HMM incorporation. A Na+/H+ antiporter, activated by the interaction of HMM with the cells microfilaments, seems to be involved in HMM action and could possibly also be a component of stimulus-secretion coupling in chromaffin cells, induced by regular agonists.
| Original language | English |
|---|---|
| Pages (from-to) | 5745-5750 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 261 |
| Issue number | 13 |
| State | Published - 1986 |
Keywords
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
- Actin Cytoskeleton/physiology
- Actins/pharmacology
- Adrenal Medulla/drug effects
- Animals
- Benzothiazoles
- Carbocyanines/pharmacology
- Catecholamines/metabolism
- Cattle
- Cell Membrane/physiology
- Chromaffin System/metabolism
- Cytoskeleton/physiology
- Fluorescent Dyes/pharmacology
- Liposomes
- Membrane Potentials/drug effects
- Myosin Subfragments/pharmacology
- Myosins/pharmacology
- Nifedipine/analogs & derivatives
- Peptide Fragments/pharmacology
- Phencyclidine/pharmacology
- Tetraethylammonium
- Tetraethylammonium Compounds/pharmacology
- Tetrodotoxin/pharmacology