The electrical response produced by dopamine across the isolated tegumental membrane of the rat submaxillary gland was examined by using the Ussing's flux chamber.
The following results were obtained :
1. As dopamine concentration increased (from 10-5M to 10-2M), the electrical responses induced by dopamine rose from 3.5mV to 10.5mV in each peak of these potential differences. These electrical responses were dependent on dopamine concentration.
2. The electrical responses induced by dopamine were antagonized by pre-applying alpha-adrenergic blocking agent, priscol.
3. The electrical responses induced by dopamine were antagonized by pre-applying beta-adrenergic blocking agent, propranolol.
4. The electrical responses induced by dopamine were antagonized by pre-applying specific dopamine receptor blocking agent, chlorpromazine.
These results suggest that there is a competitive interaction between dopamine and the antagonists (priscol, propranolol or chlorpromazine) and that alpha-, beta-adrenergic receptors and specific dopamine receptor are present in the tegumental membrane of the rat submaxillary gland.
