Title: Adenosine A3 receptors in the rat hippocampus: Lack of interaction with A1 receptors
Authors: Lopes, Luísa V. 
Rebola, Nelson 
Costenla, Ana Rita 
Halldner, Linda 
Jacobson, Marlene A. 
Oliveira, Catarina R. 
Richardson, Peter J. 
Fredholm, Bertil B. 
Ribeiro, Joaquim A. 
Cunha, Rodrigo A. 
Issue Date: 2003
Citation: Drug Development Research. 58:4 (2003) 428-438
Abstract: Adenosine acts as a neuromodulator in the hippocampus essentially through activation of inhibitory A1 receptors. Using single-cell PCR analysis, we found that CA1 pyramidal cells coexpress A1 receptor mRNA together with that of another adenosine receptor, the A3 receptor. As occurs for the A1 receptor, Western blot analysis indicated that the A3 receptor is also located in hippocampal nerve terminals. However, activation of A3 receptors with its purportedly selective agonist Cl-IBMECA (0.1-10 µM) failed to affect hippocampal synaptic transmission or to modify the evoked release of glutamate or GABA. Also, blockade of A3 receptors with MRS 1191 (5 µM) failed to affect either hypoxia- or ischemia-induced depression of hippocampal synaptic transmission. Activation of A3 receptors also failed to control A1 receptor function, as Cl-IBMECA (100 nM) did not modify the ability of CPA to displace [3H]DPCPX binding to hippocampal membranes or the A1 receptor-mediated inhibition of hippocampal synaptic transmission. However, ligand binding studies revealed that Cl-IBMECA displaced the binding of an A1 receptor agonist ([3H]R-PIA, Ki=47 nM) or antagonist ([3H]DPCPX, Ki=130 nM), which suggests that A3 receptor ligands also act on native A1 receptors. We believe that A3 receptors are expressed in hippocampal neurons and are located in hippocampal nerve terminals, though their function remains elusive. Drug Dev. Res. 58:428-438, 2003. © 2003 Wiley-Liss, Inc.
URI: http://hdl.handle.net/10316/8431
Rights: openAccess
Appears in Collections:FMUC Medicina - Artigos em Revistas Internacionais

Files in This Item:
File Description SizeFormat 
obra.pdf187.83 kBAdobe PDFView/Open
Show full item record
Google ScholarTM
Check
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.