P2Y receptors contribute to ATP-induced increases in intracellular calcium in differentiated but not undifferentiated PC12 cells.
ATP-induced Ca2+ transients were examined in individual PC12 cells of a well defined clone, before and after treatment with nerve growth factor (NGF) to induce a neurone-like phenotype. Using reverse transcriptase PCR these cells were found to express mRNA for several P2 receptors. In undifferentiated cells the ATP-induced Ca2+ response was entirely dependent on Ca2+ influx, could not be mimicked by UTP, alpha,beta-methylene ATP or dibenzoyl ATP or be blocked by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). ATP had no significant effect on levels of cyclic AMP or inositol 1,4,5-trisphosphate (InsP3). These results suggest that in undifferentiated PC12 cells ATP mainly acts on a P2X receptor, possibly the P2X4 subtype. After treatment with NGF for 7 days the ATP response was increased and partially sensitive to PPADS. A component of the ATP-induced Ca2+ increase was due to mobilisation of intracellular Ca2+ stores and another to capacitative Ca2+ entry. UTP caused an increase in intracellular Ca2+, and InsP3 formation could be stimulated by ATP and UTP. ATP also caused a small increase in cyclic AMP, but this was abolished in the presence of indomethacin. Thus, after NGF treatment ATP acts partially via a P2Y receptor, possibly the P2Y2 subtype.
Arslan
G
G
Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden. giulia.arslan@fyfa.ki.se
Filipeanu
C M
CM
Irenius
E
E
Kull
B
B
Clementi
E
E
Allgaier
C
C
Erlinge
D
D
Fredholm
B B
BB
D000255:Adenosine Triphosphate / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D020932:Nerve Growth Factor / Q000494:pharmacology* / Q000502:physiology; D016716:PC12 Cells; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000187:drug effects* / Q000378:metabolism; D014544:Uridine Triphosphate / Q000494:pharmacology* / Q000502:physiology
D015220:Calcium Channels; D010975:Platelet Aggregation Inhibitors; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D011732:Pyridoxal Phosphate; D000255:Adenosine Triphosphate; D020932:Nerve Growth Factor; D002118:Calcium; D014544:Uridine Triphosphate