4-Aminopyridine (4-AP) augments Ca(2+)-dependent action potential and changes oscillatory firing patterns in rat cerebellar Purkinje cells.
Intracellular recordings in cerebellar slice preparation showed that applications of 4-AP altered the pattern of oscillatory firing activity in Purkinje cells (PCs), especially yielding pronounced changes in action potential shape. 4-AP increased the amplitude and duration of action potential significantly and decreased the spike frequency. After 4-AP application, the duration of bursting was prolonged and the duration of after-burst hyperpolarization was progressively shortened. In all PCs tested, the rhythmicity of oscillatory firing activity was abolished completely at the steady state. These results suggest that 4-AP-sensitive currents determine the shape and frequency of individual Ca(2+)-dependent action potentials as well as maintaining oscillatory firing activity in PCs.
Seo
W S
WS
Department of Nursing, Inha University College of Medicine, Inchon, Korea. wschang@dragon.inha.ac.kr
Shin
J H
JH
Suh
C K
CK
D015761:4-Aminopyridine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D004594:Electrophysiology; D066298:In Vitro Techniques; D009991:Oscillometry; D011689:Purkinje Cells / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015761:4-Aminopyridine; D002118:Calcium