Presence of dinucleotide and ATP receptors in human cerebrocortical synaptic terminals

Eur J Pharmacol. 1999 Feb 5;366(2-3):159-65. doi: 10.1016/s0014-2999(98)00922-4.

Abstract

Human cerebrocortical synaptic terminals elicited concentration-dependent Ca2+ transients after Ap5A (diadenosine pentaphosphate) and ATP stimulation, with EC50 values of 23.44 +/- 3.70 microM and 11.48 +/- 2.12 microM, respectively. The lack of cross-desensitisation and the selective antagonism by Ip5I (diinosine pentaphosphate), suggests the activation of a dinucleotide receptor by Ap5A, and a P2X receptor by ATP. Ap5A Ca2+ transients were partially abolished by omega-conotoxin GVI-A (53%), suggesting the participation of a N-type Ca2+ channel in the dinucleotide response. ATP effect on Ca2+ entry was abolished by nicardipine (44%) and by omega-conotoxin GVI-A (52%), suggesting the participation of L- and N-type Ca2+ channels. These data suggest that Ap5A and ATP activate dinucleotide and P2X receptors, respectively, in human brain synaptic terminals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Binding, Competitive
  • Calcium / pharmacology
  • Calcium Channel Blockers / pharmacology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / metabolism
  • Cerebral Cortex / physiology*
  • Dinucleoside Phosphates / pharmacology
  • Humans
  • In Vitro Techniques
  • Inosine Nucleotides / pharmacology
  • Membrane Potentials / drug effects
  • Nicardipine / pharmacology
  • Nickel / pharmacology
  • Presynaptic Terminals / drug effects
  • Presynaptic Terminals / metabolism
  • Presynaptic Terminals / physiology*
  • Purinergic P2 Receptor Antagonists
  • Pyridoxal Phosphate / analogs & derivatives
  • Pyridoxal Phosphate / pharmacology
  • Rabbits
  • Receptors, Purinergic P1 / drug effects
  • Receptors, Purinergic P1 / metabolism*
  • Receptors, Purinergic P2 / metabolism*
  • Synaptosomes / drug effects
  • Synaptosomes / physiology
  • Vasoconstrictor Agents / pharmacology
  • Venoms / pharmacology

Substances

  • Calcium Channel Blockers
  • Dinucleoside Phosphates
  • Inosine Nucleotides
  • Purinergic P2 Receptor Antagonists
  • Receptors, Purinergic P1
  • Receptors, Purinergic P2
  • Vasoconstrictor Agents
  • Venoms
  • pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid
  • P(1),P(5)-di(adenosine-5'-)pentaphosphate
  • Pyridoxal Phosphate
  • Nickel
  • Adenosine Triphosphate
  • Nicardipine
  • Calcium