Activation of protein kinase C by the error signal from a basal ganglia-forebrain circuit in the zebra finch song control nuclei.
An error signal from the anterior forebrain pathway (AFP) in the songbird brain is necessary for juvenile song learning and adult song maintenance. It induces the expression of protein kinase C (PKC) which is related to the plasticity in the robust nucleus of the archistriatum (RA), one of the song control nuclei in the forebrain. The glutamatergic inputs from the AFP activate mainly the NMDA receptors of the RA neurons. In order to clarify the molecular mechanism of error signal-induced PKC activation, two experiments were carried out. First, Ca2+ concentration was measured in a brain slice preparation from zebra finches using the fluorescent Ca2+ indicator Fura 2-AM. Glutamate increased the intracellular Ca2+ concentration ([Ca2+](i)) in RA neurons. This increase was inhibited by the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (AP5). Second, we examined the expression of PKC in the RA slice preparation after stimulation with glutamate for 10 min using PKCbeta1 fluorescence immunohistochemistry. Glutamate induced the activation of PKC as the translocation from the cytosol to the cell membrane, and the translocation was inhibited by AP5. These results indicate that the translocation of the PKC caused by the [Ca2+](i) elevation through NMDA receptors is concerned with the initial stage of error signal-induced plasticity in the RA.
Yoshida
Yumi
Y
Department of Physis, Faculty of Science, Tokyo University, Tokyo 162-8601, Japan.
Yamada
Takenori
T
Sakaguchi
Hironobu
H
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D001479:Basal Ganglia / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D018683:Excitatory Amino Acid Agents / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005455:Fluorescent Antibody Technique / Q000379:methods; D016257:Fura-2 / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008474:Medial Forebrain Bundle / Q000166:cytology / Q000378:metabolism; D016548:Prosencephalon / Q000502:physiology*; D011493:Protein Kinase C / Q000145:classification / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D020308:Songbirds; D013997:Time Factors; D014828:Vocalization, Animal / Q000502:physiology*
D018683:Excitatory Amino Acid Agents; D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid; D015763:2-Amino-5-phosphonovalerate; D011493:Protein Kinase C; D002118:Calcium; D016257:Fura-2