Abstract
The relaxing effect of dopamine on isolated coronary vessels and the activating effect of dopamine on large-conductance, calcium-activated potassium channels (BKCa) in the membrane of coronary myocytes were investigated with isometric tension recording method and patch-clamp technique. Tension studies demonstrated that dopamine relaxed prostaglandin F2α-induced contraction of porcine coronary arteries in a concentration-dependent manner, but it failed to relax high [K+] precontracted arteries. In cell attached patch experiments, dopamine caused a significant increase in the mean opening probability of the BKCa channels. The effect of dopamine was not blocked by propranolol but was completely prevented by SCH23390, a selective DA1 antagonist. These results demonstrate that dopamine relaxes prostaglandin F2α-induced contraction of porcine coronary arteries via activation of DA1 receptors which causes stimulation of BKCa channel activity.
| Original language | American English |
|---|---|
| Journal | Chinese Journal of Pharmacology and Toxicology |
| Volume | 14 |
| State | Published - Jan 1 2000 |
Keywords
- 3
- 4
- 5 tetrahydro 3 methyl 5 phenyl 1h 3 benzazepin 7 ol hydrogen maleate
- 8 chloro 2
- Coronary vessels
- Dopamine
- Muscle
- Patch clamp technique
- Potassium channels
- Receptors
- animal tissue
- artery muscle
- article
- calcium
- coronary artery dilatation
- dopamine
- dopamine 1 receptor blocking agent
- drug effect
- muscle isometric contraction
- muscle tone
- nonhuman
- patch clamp
- potassium
- potassium channel
- propranolol
- prostaglandin F2 alpha
- smooth
- smooth muscle fiber
- swine
- vascular
Disciplines
- Circulatory and Respiratory Physiology