UTP- and ATP-triggered transmitter release from rat sympathetic neurones via separate receptors.
In rat cultured sympathetic neurones, UDP, UTP and ATP at micromolar concentrations triggered Ca(2+)-dependent and tetrodotoxin-sensitive [3H]-noradrenaline release. The overflow evoked by UTP or ATP was similar at 100 mumol l-1, the concentration used in all subsequent experiments. Pre-exposure of the neurones to 100 mumol l-1 UTP significantly reduced ensuing secretory effects of UTP but not of ATP. Conversely, pre-exposure to ATP diminished the overflow due to ATP but not that due to UTP. In the presence of 10 mumol l-1 pyridoxal-5'-phosphate or 30 mumol l-1 suramin, the secretory response to ATP was reduced, but the effect of UTP was unaltered. Zn2+ (10 mumol l-1) reduced the overflow triggered by UTP, but increased the overflow due to ATP. These results indicate the presence of separate receptors for pyrimidine nucleotides and for purine nucleotides which both trigger transmitter release.
Boehm
S
S
Institute of Neuropharmacology, University of Vienna, Austria.
Huck
S
S
Illes
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism*; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014530:Uridine Diphosphate / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter; D014530:Uridine Diphosphate; D000255:Adenosine Triphosphate; D014544:Uridine Triphosphate; D009638:Norepinephrine