NMDA receptor contribution to the climbing fiber response in the adult mouse Purkinje cell.
Among integrative neurons displaying long-term synaptic plasticity, adult Purkinje cells seemed to be an exception by lacking functional NMDA receptors (NMDA-Rs). Although numerous anatomical studies have shown both NR1 and NR2 NMDA-R subunits in adult Purkinje cells, patch-clamp studies failed to detect any NMDA currents. Using more recent pharmacological and immunodetection tools, we demonstrate here that Purkinje cells from adult mice respond to exogenous NMDA application and that postsynaptic NMDA-Rs carry part of the climbing fiber-mediated EPSC (CF-EPSC), with undetectable contribution from presynaptic or polysynaptic NMDA currents. We also detect NR2-A/B subunits in adult Purkinje cells by immunohistochemistry. The NMDA-mediated CF-EPSC is barely detectable before 3 weeks postnatal. From the end of the third week, the number of cells displaying the NMDA-mediated CF-EPSC rapidly increases. Soon, this EPSC becomes detectable in all the Purkinje cells but is still very small. Its amplitude continues to increase until 12 weeks after birth. In mature Purkinje cells, we show that the NMDA-Rs contribute to the depolarizing plateau of complex spikes and increase their number of spikelets. Together, these observations demonstrate that mature Purkinje cells express functional NMDA receptors that become detectable in CF-EPSCs at approximately 21 d after birth and control the complex spike waveform.
Piochon
Claire
C
Université Pierre et Marie Curie-Paris 6, Unité Mixte de Recherche 7102, Centre National de la Recherche Scientifique, Laboratoire Neurobiologie des Processus Adaptifs, Equipe Développement et Vieillissement du Système Nerveux, 75005 Paris, France.
Irinopoulou
Theano
T
Brusciano
Daniel
D
Bailly
Yannick
Y
Mariani
Jean
J
Levenes
Carole
C
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002531:Cerebellum / Q000166:cytology; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D016202:N-Methylaspartate / Q000494:pharmacology; D009412:Nerve Fibers / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D011689:Purkinje Cells / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism / Q000502:physiology*
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; C120997:NR2A NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate