Alvarez E O, Ruarte M B
Unidad de Neuroquímica y Farmacología del Comportamiento, Farmacología, Facultad de Ciencias Médicas,Universidad Nacional de Cuyo, Casilla de Correo 33, Mendoza 5500, Argentina.
Behav Brain Res. 2001 Sep 14;123(2):143-53. doi: 10.1016/s0166-4328(01)00190-5.
The possible role of glutamic acid locally applied into the nucleus accumbens on exploratory behaviours measured in 'conflictive' and 'non-conflictive' environments was studied in adult male rats. As a model of conflictive environment, the elevated asymmetric-plus maze (APM) was used. As a model of a non-conflictive environment, a modified holeboard enriched with an object (OVM) was used. In order to characterize the possible glutamic acid receptors involved, the following antagonists were also used: AP3 (antagonist of the metabotropic glutamic acid receptor), AP7 (antagonist of NMDA glutamic acid receptor, and CNQX (antagonists of kainate/AMPA glutamic acid receptor). Results showed that injection of glutamic acid into the nucleus accumbens induced in the APM a decrease of exploration and an increase of the permanency score (non-exploratory behaviours) of the 'High and Low wall' arm. However, in the 'Two High Walls' arm, glutamic acid decreased permanency. In the OVM, no major changes in the motor activity were observed with glutamic acid. Nevertheless, the vertical activity (an index of rearing) and head-dipping were inhibited by the amino-acid treatment. In the APM, the decrease of exploration induced by glutamic acid was blocked by all three receptor antagonists. In the non-exploratory behaviours, the facilitatory effect observed in the 'High and Low walls' arm was blocked only by AP7 and CNQX. The inhibitory action of glutamic acid on the permanency score in the 'Two High Walls' arm was not blocked by the receptors antagonists. In the OVM, AP7 and CNQX were effective in blocking the inhibition of glutamic acid on the vertical activity, but in head-dipping, only AP3 and CNQX were able to block the effect of the amino acid on this behaviour. In conclusion, the present results are compatible with the concept that glutamatergic input fibres to the nucleus accumbens modulate the expression of exploratory behaviour induced by novelty in conflictive and non-conflictive conditions.
研究了向成年雄性大鼠伏隔核局部注射谷氨酸对在“冲突性”和“非冲突性”环境中所测量的探究行为的可能作用。作为冲突性环境的模型，使用了高架不对称十字迷宫（APM）。作为非冲突性环境的模型，使用了一个装有物体的改良洞板（OVM）。为了确定可能涉及的谷氨酸受体，还使用了以下拮抗剂：AP3（代谢型谷氨酸受体拮抗剂）、AP7（NMDA谷氨酸受体拮抗剂）和CNQX（海人藻酸/AMPA谷氨酸受体拮抗剂）。结果表明，向伏隔核注射谷氨酸会使APM中的探究行为减少，“高低壁”臂的停留分数（非探究行为）增加。然而，在“双高壁”臂中，谷氨酸会降低停留时间。在OVM中，未观察到谷氨酸对运动活动有重大影响。尽管如此，氨基酸处理抑制了垂直活动（一种站立指标）和探头行为。在APM中，谷氨酸诱导的探究行为减少被所有三种受体拮抗剂阻断。在非探究行为中，仅AP7和CNQX阻断了在“高低壁”臂中观察到的促进作用。谷氨酸对“双高壁”臂停留分数的抑制作用未被受体拮抗剂阻断。在OVM中，AP7和CNQX有效阻断了谷氨酸对垂直活动的抑制作用，但在探头行为方面，只有AP3和CNQX能够阻断氨基酸对该行为的影响。总之，目前的结果与以下概念相符，即向伏隔核的谷氨酸能输入纤维在冲突性和非冲突性条件下调节由新奇性诱导的探究行为的表达。
