Inactivation of adenosine A_2A receptor impairs long term potentiation in the accumbens nucleus without altering basal synaptic transmission

详细信息    查看全文

• 作者：d
  46 ; Alcantara ; P. ; Ledent ; C. ; Swillens ; S. ; Schiffmann ; S.N.
• 关键词：striatum ; field excitatory postsynaptic potential ; glutamatergic transmission ; long term potentiation ; A₁R ; adenosine A₁ receptor ; A_2AR ; adenosine A_2A receptor ; A_2AR^&minus ; /&minus ; mice ; ad
• 刊名：Neuroscience
• 出版年：2001
• 出版时间：November 23, 2001
• 年：2001
• 卷：107
• 期：3
• 页码：455-464
• 全文大小：379 K

文摘

The nucleus accumbens is considered to be critically involved in the control of complex motivated behaviors. By modulating its glutamatergic excitatory input, mesolimbic dopaminergic afferents have been implicated in the reinforcing properties of drugs of abuse. However, they might not represent the only path for influencing the accumbens output. The aim of this study was to investigate possible modulation of synaptic transmission at this glutamatergic synapse by adenosine receptors. The standard field potential recording technique was used on brain slices from wild-type and A_2A receptor-deficient mice. Neither the stimulus–response relationship nor paired-pulse facilitation was altered in the mutant mice. In both genotypes, the activation of A₁ receptors by 2-chloro-N⁶-cyclopentyladenosine reduced the field excitatory postsynaptic potential (fEPSP) slope to a similar extent. In wild-type slices, activation or blockade of A_2A receptors by 2-[4-(carboxyethyl)phenylethylamino]-5′-N-ethylcarboxamidoadenosine and 4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol, respectively, did not modify the synaptic transmission. Moreover, a long lasting pre-activation of these A_2A receptors did not influence the A₁ receptor-mediated reduction in fEPSP slope. Long term potentiation (LTP) of the 45;-amino-3-hydroxy-5-methyl-4-isoxazole proprionate (AMPA) receptor-mediated synaptic transmission could be elicited in both wild-type and A_2A receptor-deficient mice. However, LTP appeared to be quantitatively modulated by the A_2A receptor pathway since the level of potentiation was reduced in A_2A receptor-deficient mice as well as in slices of wild-type mice in which the A_2A receptor pathway was blocked. The involvement of the cAMP-dependent protein kinase was supported by the reduction in potentiation level in slices of wild-type mice treated with adenosine 3′,5′-cyclic monophosphorothiotate, 8-(4-chlorophenylthio)-Rp isomer, an inhibitor of this enzyme.