Zinc increases the excitability of dopaminergic neurons in rat substantia nigra.
The effect of zinc ions (Zn(2+)) on the neuronal excitability of substantia nigra (SN) where the zinc level is known higher in Parkinsonian brains than that in normal brains has not yet been elucidated. We, therefore, examined the effect of Zn(2+) on the intrinsic electrical properties of dopaminergic SN neurons, using a whole-cell recording method. Zn(2+) hyperpolarized dopaminergic SN neurons at resting state. Also Zn(2+) shortened the duration of evoked spikes, developed a fast afterhyperpolarization, and increased their firing frequency. Voltage-clamp studies showed that Zn(2+) decreased 4-aminopyridine-sensitive outward currents, suggesting that a transient A-like potassium channel be one of the major targets Zn(2+) can modulate in the SN neurons.
Chung
J
J
Neurophysiology Laboratory, Department of Biology and Center for Cell Signaling Research, College of Natural Sciences, Ewha Womans University, 11-1 Daehyun-dong, Seodaemun-gu, 120-750, Seoul, South Korea. jmchung@mm.ewha.ac.kr
Chang
S
S
Kim
Y
Y
Shin
H
H
D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004298:Dopamine / Q000502:physiology*; D004553:Electric Conductivity; D004594:Electrophysiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D015032:Zinc / Q000494:pharmacology*
D015761:4-Aminopyridine; D015032:Zinc; D004298:Dopamine