Effects of adenosine 5′-triphosphate (ATP) on ionic currents activated by acetylcholine (ACh) were investigated using rat pheochromocytoma PC12 cells and Xenopus oocytes expressing nicotinic receptors. In PC12 cells, ATP (10 nM to l μM) inhibited an inward current activated by ACh in not all but about 60% of cell batches. The ACh-activated current was also inhibited by ATP in Xenopus oocytes and, with a subunit combination of α3 plus β4, the inhibition was observed at concentration as low as 100 fM. Uridine 5′-triphosphate (UTP) induced a similar inhibition of the ACh-activated current both in PC12 cells and Xenopus oocytes. These and other sproperties suggest that the current reduction by ATP is not mediated through conventional P2-purinoceptors.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)