Two distinct P2 purinergic receptors, P2Y and P2U, are coupled to phospholipase C in mouse pineal gland tumor cells

J Neurochem. 1997 Apr;68(4):1622-32. doi: 10.1046/j.1471-4159.1997.68041622.x.

Abstract

We found that extracellular ATP can increase the intracellular Ca2+ concentration ([Ca2+]i) in mouse pineal gland tumor (PGT-beta) cells. Studies of the [Ca2+]i rise using nucleotides and ATP analogues established the following potency order: ATP, adenosine 5'-O-(3-thiotriphosphate) > or = UTP > 2-chloro-ATP > 3'-O-(4-benzoyl)benzoyl ATP, GTP > or = 2-methylthio ATP, adenosine 5'-O-(2-thiodiphosphate) (ADP beta S) > CTP. AMP, adenosine, alpha,beta-methyleneadenosine 5'-triphosphate, beta,gamma-methyleneadenosine 5'-triphosphate, and UMP had little or no effect on the [Ca2+]i rise. Raising the extracellular Mg2+ concentration to 10 mM decreases the ATP- and UTP-induced [Ca2+]i rise, because the responses depend on the ATP4- and UTP4- concentrations, respectively. The P2U purinoceptor-selective agonist UTP and the P2Y purinoceptor-selective agonist ADP beta S induce inositol 1,4,5-trisphosphate generation in a concentration-dependent manner with maximal effective concentrations of approximately 100 microM. In sequential stimulation, UTP and ADP beta S do not interfere with each other in raising the [Ca2+]i. Costimulation with UTP and ADP beta S results in additive inositol 1,4,5-trisphosphate generation to a similar extent as is achieved with ATP alone. Pretreatment with pertussis toxin inhibits the action of UTP and ATP by maximally 45-55%, whereas it has no effect on the ADP beta S response. Treatment with 1 microM phorbol 12-myristate 13-acetate inhibits the ADP beta S-induced [Ca2+]i rise more effectively than the ATP- and UTP-induced responses. These results suggest that P2U and P2Y purinoceptors coexist on PGT-beta cells and that both receptors are linked to phospholipase C.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / analogs & derivatives
  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / analogs & derivatives
  • Adenosine Triphosphate / pharmacology
  • Animals
  • Antigens, Polyomavirus Transforming
  • Arylamine N-Acetyltransferase / metabolism
  • Biomarkers
  • Calcium / metabolism
  • Carcinogens / pharmacology
  • Cell Line, Transformed / chemistry
  • Cell Line, Transformed / drug effects
  • Cell Line, Transformed / enzymology
  • Dose-Response Relationship, Drug
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Magnesium / pharmacology
  • Mice
  • Pertussis Toxin
  • Pineal Gland / chemistry
  • Pineal Gland / cytology*
  • Receptors, Purinergic P2 / chemistry
  • Receptors, Purinergic P2 / metabolism*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thionucleotides / pharmacology
  • Tryptophan Hydroxylase / metabolism
  • Type C Phospholipases / metabolism*
  • Uridine Triphosphate / pharmacology
  • Virulence Factors, Bordetella / pharmacology

Substances

  • Antigens, Polyomavirus Transforming
  • Biomarkers
  • Carcinogens
  • Receptors, Purinergic P2
  • Thionucleotides
  • Virulence Factors, Bordetella
  • adenosine 5'-O-(2-thiodiphosphate)
  • Adenosine Diphosphate
  • Inositol 1,4,5-Trisphosphate
  • Adenosine Triphosphate
  • Tryptophan Hydroxylase
  • Arylamine N-Acetyltransferase
  • Pertussis Toxin
  • Type C Phospholipases
  • Magnesium
  • Tetradecanoylphorbol Acetate
  • Calcium
  • Uridine Triphosphate