Adenosine receptor agonists inhibit K+-evoked Ca2+ uptake by rat brain cortical synaptosomes

J Neurochem. 1982 Sep;39(3):700-8. doi: 10.1111/j.1471-4159.1982.tb07949.x.


The uptake of Ca2+ by a K+-depolarized rat brain cerebral cortical crude synaptosomal preparation (P2 fraction) was investigated. The characteristics of the Ca2+ uptake system are similar to those observed by other investigators. The preparation is also a suitable model with which to study the effects of adenosine on Ca2+ uptake and neurotransmitter release, as it is generally accepted that K+-evoked Ca2+ uptake is intimately related to depolarization-induced release of neurotransmitters. We have demonstrated that an extracellular receptor is involved in mediating the adenosine-evoked inhibition of K+-evoked Ca2+ uptake. The pharmacological properties of the receptor suggest that it may be similar in some respects to the A2-receptor associated with adenylate cyclase. The adenosine uptake inhibitor, dipyridamole, potentiated the action of adenosine, suggesting that re-uptake is important in controlling the extracellular adenosine concentration and thus in the regulation of the adenosine receptor. The adenosine receptor antagonist theophylline inhibited the effects of adenosine. Calmodulin inhibited K+-evoked uptake of Ca2+ by the synaptosomal fraction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / metabolism*
  • Adenosine / pharmacology
  • Animals
  • Biological Transport, Active / drug effects
  • Calcium / metabolism*
  • Cerebral Cortex / metabolism*
  • Kinetics
  • Male
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Potassium / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Receptors, Cell Surface / metabolism*
  • Receptors, Purinergic
  • Synaptosomes / drug effects
  • Synaptosomes / metabolism*


  • Receptors, Cell Surface
  • Receptors, Purinergic
  • Adenosine
  • Potassium
  • Calcium