1987 Volume 84 Issue 3 Pages 653-660
Inhibitory mechanism of dopamine on rat gastric motility was investigated in association with acetylcholine (ACh) release. Vagotomy or sympathectomy had no effect on the inhibitory action of dopamine, indicating that the site of action of dopamine is in the gastric wall. Electrical transmural stimulation induced a neurogenic muscular contraction and [3H] ACh release from the muscle strips of rat stomach preloaded with [3H] choline. Dopamine at the concentration of 10-4M inhibited significantly by 41% the [3H] ACh release induced by electrical transmural stimulation.
The inhibitory effect of dopamine was significantly antagonized by domperidone, but not by adrenergic blocking agents such as phentolamine or propranolol.
These results indicate that dopamine plays an important role in the regulation of gastric motility by reducing ACh release through specific dopamine receptor located on the postganglionic cholinergic neurons.