α-Adrenoceptive dual modulation of inhibitory GABAergic inputs to Purkinje cells in the mouse cerebellum

• Hirono Moritoshi

  Neuronal Circuit Mechanisms Research Group, BSI, RIKEN, Wako, Japan

• Matsunaga Wataru

  Neuronal Circuit Mechanisms Research Group, BSI, RIKEN, Wako, Japan

• Obata Kunihiko

  Neuronal Circuit Mechanisms Research Group, BSI, RIKEN, Wako, Japan

Bibliographic Information

Other Title

• アルファーアドレナリン受容体による小脳抑制性シナプス伝達の二重修飾作用

Abstract

In the cerebellar cortex, previous reports indicated that noradrenaline (NA) enhances inhibitory synaptic transmission via β-adrenoceptor-pathways. However, the effects of α-adrenoceptor activation on cerebellar inhibitory postsynaptic currents (IPSCs) have not yet been fully understood. Therefore, we investigated the effects of the α₁- or α₂-adrenoceptor agonist on IPSCs recorded from mouse Purkinje cells (PCs). The selective α₁-adrenoceptor agonist phenylephrine (PE) increased both the frequency and amplitude of spontaneous IPSCs (sIPSCs). PE also enhanced the amplitude of evoked IPSCs (eIPSCs) and increased the frequency but not the amplitude of miniature IPSCs (mIPSCs). Moreover, PE decreased the paired-pulse ratio of eIPSCs and did not change GABA receptor sensitivity in PCs. Conversely, the selective α₂-adrenoceptor agonist clonidine significantly reduced both the frequency and the amplitude of sIPSCs. Neither eIPSCs nor mIPSCs were affected by clonidine. Furthermore, presynaptic cell-attached recordings showed that spontaneous activity of GABAergic interneurons was enhanced by PE, while reduced by clonidine. These results suggest that NA enhances inhibitory neurotransmitter release via α₁-adrenoceptors, which are expressed in presynaptic terminals and somatodendritic domains, whereas suppresses the excitability of interneurons via α₂-adrenoceptors, which are expressed in presynaptic somatodendritic domains. Thus, cerebellar α-adrenoceptors play roles in a presynaptic dual modulation of GABAergic inputs from interneurons to PCs. [J Physiol Sci. 2006;56 Suppl:S161]

Journal

• Proceedings of Annual Meeting of the Physiological Society of Japan

  Proceedings of Annual Meeting of the Physiological Society of Japan 2006 (0), 161-161, 2006

  PHYSIOLOGICAL SOCIETY OF JAPAN

Keywords

• noradrenaline
• α-adrenoceptor
• inhibitory synapse
• cerebellum

Details

• CRID: 1390001205727482880
• NII Article ID: 130005448415
• DOI: 10.14849/psjproc.2006.0_161_3
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed