Presence of different ATP receptors on rat midbrain single synaptic terminals. Involvement of the P2X(3) subunits

Neurosci Lett. 2001 Apr 6;301(3):159-62. doi: 10.1016/s0304-3940(01)01614-7.

Abstract

Adenosine 5'-triphosphate (ATP) stimulates a [Ca(2+)](i) increase via specific ionotropic receptors, termed P2X receptors, in rat midbrain presynaptic terminals. A microfluorimetric technique enabled study of the [Ca(2+)](i) increase in isolated single synaptic terminals, showing that 33.4+/-2.5% of them responded to ATP. Immunological studies carried out, after functional studies, with specific anti-P2X receptor subunit antibodies showed only positive labelling with anti-P2X(3) antibodies in 23.5+/-1.7% of the terminals. All positively P2X(3) labelled synaptic terminals responded to ATP. Nevertheless, not all of them responded to alpha,beta-meATP, these representing 6.7+/-1.5% of the total. In addition, 9.8+/-2.3% of the terminals responded to ATP but exhibit negative P2X(3)-labelling. These results demonstrate the existence of a heterogeneous population of ionotropic ATP receptors at the presynaptic level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytophotometry
  • Immunohistochemistry
  • Mesencephalon / chemistry*
  • Mesencephalon / cytology
  • Presynaptic Terminals / chemistry*
  • Rats
  • Receptors, Purinergic P2 / analysis*
  • Receptors, Purinergic P2X3
  • Synaptophysin / analysis
  • Synaptosomes / chemistry

Substances

  • P2rx3 protein, rat
  • Receptors, Purinergic P2
  • Receptors, Purinergic P2X3
  • Synaptophysin