Delayed appearance of G-protein coupled signal transduction system in developing cerebellar Purkinje cell dendrites.
To investigate the relation between the function of Ca(2+)-activated K+ channels and phosphoinositide turnover, we have examined the physiological and pharmacological characteristics of ionotropic and metabotropic quisqualate (QA) receptors in rat cerebellar Purkinje cells during development using the slice-patch method combined with Ca2+ imaging. The typical response to QA obtained from a rat on postnatal day (PND) 21 consisted of three components: (1) a fast inactivating inward current, (2) a slow inward current, and (3) a slow outward current. The slow inward current was abolished in Ca(2+)-free medium, while the fast inactivating inward current and the slow outward current remained unaffected. The slow outward current which appeared to be activated via a metabotropic receptor was not observed in the Purkinje cell of PND 7 rat, in which dendrites were poorly developed but its amplitude increased linearly with PND. QA caused significant increases in [Ca2+]i in the fully developed dendritic region of the Purkinje cells even in Ca(2+)-free medium, suggesting a dendritic localization of the metabotropic receptors.
Takagi
H
H
Department of Molecular Neurobiology, School of Human Sciences, Waseda University, Tokorozawa, Japan.
Takimizu
H
H
Yoshioka
T
T
Suzuki
N
N
Ito
E
E
Kudo
Y
Y
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism / Q000502:physiology*; D004594:Electrophysiology; D019204:GTP-Binding Proteins / Q000502:physiology*; D011689:Purkinje Cells / Q000378:metabolism / Q000502:physiology*; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D011930:Reaction Time; D015398:Signal Transduction
D016318:Quisqualic Acid; D019204:GTP-Binding Proteins; D002118:Calcium