Department of Pharmacology, Nihon University School of Dentistry, Tokyo, Japan.
Neuroscience. 2010 Apr 28;167(1):31-9. doi: 10.1016/j.neuroscience.2010.01.054. Epub 2010 Feb 1.
The role of GABA(A) and GABA(B) receptors in the substantia nigra pars reticulata and the globus pallidus in turning behaviour of rats was studied. Unilateral injection of the GABA(A) receptor agonist muscimol (25 and 50 ng) into the substantia nigra pars reticulata elicited contralateral pivoting, namely tight head-to-tail turning marked by abnormal hindlimb backward stepping. This effect was GABA(A) receptor specific, since it was dose-dependent and prevented by co-administration of the GABA(A) receptor antagonist bicuculline (100 and 200 ng) which alone did not elicit turning behaviour. Unilateral injection of the GABA(B) receptor agonist baclofen (100 and 200 ng) into the substantia nigra pars reticulata also produced contralateral pivoting. This effect was GABA(B) receptor specific, since it was dose-dependent and inhibited by the GABA(B) receptor antagonist CGP 55845 (200 ng) which alone did not elicit turning behaviour. In contrast, unilateral injection of bicuculline (100 and 200 ng) into the globus pallidus produced contralateral circling, namely turning marked by normal stepping. This effect was GABA(A) receptor specific, since it was dose-dependent and prevented by muscimol (50 ng), which alone did not elicit turning behaviour. Unilateral injection of baclofen (100 and 200 ng) into the globus pallidus dose-dependently produced ipsilateral pivoting; this effect was inhibited by CGP 55845 (200 ng), which alone did not elicit turning behaviour. The present study demonstrates that GABA(A) and GABA(B) receptors in the globus pallidus and the substantina nigra pars reticulata play differential roles in the production of turning behaviour. This study underlines the notion that the two types of turning, namely pivoting and circling, are valid tools to map out the information flow across the basal ganglia.
研究了 GABA(A)和 GABA(B)受体在黑质网状部和苍白球中的作用，以观察它们对大鼠转向行为的影响。将 GABA(A)受体激动剂 muscimol（25 和 50ng）单侧注射到黑质网状部会引起对侧旋转，即表现为异常的后腿向后踏步的紧密头尾式旋转。这种效应是 GABA(A)受体特异性的，因为它呈剂量依赖性，并且可以被 GABA(A)受体拮抗剂 bicuculline（100 和 200ng）所阻止，而 bicuculline 单独注射不会引起转向行为。将 GABA(B)受体激动剂 baclofen（100 和 200ng）单侧注射到黑质网状部也会引起对侧旋转。这种效应是 GABA(B)受体特异性的，因为它呈剂量依赖性，并且可以被 GABA(B)受体拮抗剂 CGP 55845（200ng）所抑制，而 CGP 55845 单独注射不会引起转向行为。相反，将 bicuculline（100 和 200ng）单侧注射到苍白球会引起对侧盘旋，即表现为正常踏步的旋转。这种效应是 GABA(A)受体特异性的，因为它呈剂量依赖性，并且可以被 muscimol（50ng）所阻止，而 muscimol 单独注射不会引起转向行为。将 baclofen（100 和 200ng）单侧注射到苍白球会剂量依赖性地引起同侧旋转；这种效应可以被 CGP 55845（200ng）所抑制，而 CGP 55845 单独注射不会引起转向行为。本研究表明，GABA(A)和 GABA(B)受体在苍白球和黑质网状部中在产生转向行为方面发挥着不同的作用。本研究强调了这样一种观点，即两种类型的转向，即旋转和盘旋，是映射基底神经节信息流动的有效工具。
