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Autoradiography of P 2X ATP receptors in the rat brain
Author(s) -
Balcar Vladimir J.,
Li Yi,
Killinger Suzanne,
Bennett Maxwell R.
Publication year - 1995
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1995.tb15877.x
Subject(s) - suramin , adenosine , adenosine triphosphate , chemistry , receptor , ouabain , adenosine receptor , ligand (biochemistry) , p2y receptor , radioligand , adenosine a1 receptor , biochemistry , biology , biophysics , purinergic receptor , agonist , organic chemistry , sodium
1 Binding of a P 2 , receptor specific radioligand, [ 3 H]‐α,β‐methylene adenosine triphosphate ([ 3 H]‐m43‐MeATP) to sections of rat brain was reversible and association/dissociation parameters indicated that it consisted of two saturable components. Non‐specific binding was very low (<7% at 10 nM ligand concentration). 2 The binding was completely inhibited by suramin (IC 50 ∼ 14–26 μ m ) but none of the ligands specific for P 2y receptors such as 2‐methylthio‐adenosine triphosphate (2‐methyl‐S‐ATP) and 2‐chloro‐adenosine triphosphate (2‐C1‐ATP) nor 2‐methylthio‐adenosine diphosphate (2‐methyl‐S‐ADP) a ligand for the P 2 receptor on blood platelets (′P 2T ′ type) produced strong inhibitions except for P 1 , P 4 ‐di(adenosine‐5′)tetraphosphate (A p4 A). 3 Inhibitors of Na + , K + ‐dependent adenosine triphosphatase (ATPase) ouabain, P 1 ‐ligand adenosine and an inhibitor of transport of, respectively, adenosine and cyclic nucleotides, dilazep, had no effect. 4 The highest density of P 2x binding sites was found to be in the cerebellar cortex but the binding sites were present in all major brain regions, especially in areas known to receive strong excitatory innervation.