ZM 241385, an adenosine A(2A) receptor antagonist, inhibits hippocampal A(1) receptor responses.
4-(2-[7-amino-2-(2-furyl¿1,2,4¿-triazolo¿2,3a¿-¿1,3, 5¿triazin-5-yl-amino]ethyl)phenol (ZM 241385) has been used as an antagonist of adenosine A(2A) receptors, exhibiting high selectivity over adenosine A(1) receptors. We now report that ZM 241385 (10-50 nM) attenuated the inhibitory action of N(6)-cyclopentyladenosine (10 nM) and R(-)-N(6)-phenylisopropyladenosine (R-PIA, 20 nM), two selective adenosine A(1) receptor agonists, on hippocampal population spike amplitude. This effect is unlikely to be a direct antagonism of adenosine A(1) receptor since the K(i) of ZM 241385 to displace [3H]PIA (2 nM) binding, from hippocampal membranes ranged from 0.8 to 1.9 microM. These results question the usefulness of ZM 241385 to define adenosine A(2A) receptors actions in functional studies.
Lopes
L V
LV
Laboratory of Neurosciences, Faculty of Medicine, University of Lisbon, 1649-028, Lisbon, Portugal.
Cunha
R A
RA
Ribeiro
J A
JA
D000818:Animals; D015226:Dinucleoside Phosphates / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010660:Phenylisopropyladenosine / Q000378:metabolism; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1 / Q000187:drug effects* / Q000502:physiology; D014227:Triazines / Q000494:pharmacology*; D014230:Triazoles / Q000494:pharmacology*
D015226:Dinucleoside Phosphates; D004791:Enzyme Inhibitors; D058915:Purinergic P1 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385; C013907:cytidylyl adenosine; D010660:Phenylisopropyladenosine