Subtypes of substantia nigra dopaminergic neurons revealed by apamin: Autoradiographic and electrophysiological studies

X. Gu, A. L. Blatz, D. C. German

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In the intact animal, some substantia nigra dopaminergic neurons exhibit regular and some exhibit burst firing patterns. In the in vitro slice preparation, however, all dopaminergic neurons exhibit a nonburst firing pattern. Burst firing patterns are thought to be regulated, in part, by a small conductance calcium-activated potassium channel (SK channels). To test whether SK channels reside within the midbrain dopaminergic cell regions of the mouse, receptor autoradiographic experiments were conducted with the SK channel antagonist, 125I-apamin. To determine whether SK channels play a role in burst firing pattern generation in substantia nigra dopaminergic neurons, changes in firing patterns of these cells were examined in the in vitro slice preparation following apamin superfusion (1-1000 nM). It was demonstrated that a) specific binding of radiolabeled apamin was found within the dopaminergic cell regions of the substantia nigra pars compacta and ventral tegmental area (2.7-4.7 fmol/mg tissue): b) the firing patterns of less than half of the dopaminergic neurons were changed from a regular pattern to that of a burster with concentrations as low as I nM, but the firing patterns of many neurons were not changed by the drug; and c) blockade of the SK channel did not interfere with the inhibitory effects of dopamine on dopaminergic neuronal impulse flow, indicating that the known hyperpolarizing effects mediated by this dopamine receptor are not importantly mediated via the SK channel.

Original languageEnglish (US)
Pages (from-to)435-440
Number of pages6
JournalBrain Research Bulletin
Volume28
Issue number3
DOIs
StatePublished - 1992

Fingerprint

Apamin
Dopaminergic Neurons
Substantia Nigra
Small-Conductance Calcium-Activated Potassium Channels
Ventral Tegmental Area
Dopamine Receptors
Mesencephalon
Dopamine
Neurons
Pharmaceutical Preparations
In Vitro Techniques

Keywords

  • Apamin
  • Autoradiography
  • Ca-activated K-channel
  • Dopaminergic neurons
  • Electrophysiology
  • Mouse
  • Substantia nigra

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Subtypes of substantia nigra dopaminergic neurons revealed by apamin : Autoradiographic and electrophysiological studies. / Gu, X.; Blatz, A. L.; German, D. C.

In: Brain Research Bulletin, Vol. 28, No. 3, 1992, p. 435-440.

Research output: Contribution to journalArticle

@article{85e25027ca1b4389bdc603d971d7b71a,
title = "Subtypes of substantia nigra dopaminergic neurons revealed by apamin: Autoradiographic and electrophysiological studies",
abstract = "In the intact animal, some substantia nigra dopaminergic neurons exhibit regular and some exhibit burst firing patterns. In the in vitro slice preparation, however, all dopaminergic neurons exhibit a nonburst firing pattern. Burst firing patterns are thought to be regulated, in part, by a small conductance calcium-activated potassium channel (SK channels). To test whether SK channels reside within the midbrain dopaminergic cell regions of the mouse, receptor autoradiographic experiments were conducted with the SK channel antagonist, 125I-apamin. To determine whether SK channels play a role in burst firing pattern generation in substantia nigra dopaminergic neurons, changes in firing patterns of these cells were examined in the in vitro slice preparation following apamin superfusion (1-1000 nM). It was demonstrated that a) specific binding of radiolabeled apamin was found within the dopaminergic cell regions of the substantia nigra pars compacta and ventral tegmental area (2.7-4.7 fmol/mg tissue): b) the firing patterns of less than half of the dopaminergic neurons were changed from a regular pattern to that of a burster with concentrations as low as I nM, but the firing patterns of many neurons were not changed by the drug; and c) blockade of the SK channel did not interfere with the inhibitory effects of dopamine on dopaminergic neuronal impulse flow, indicating that the known hyperpolarizing effects mediated by this dopamine receptor are not importantly mediated via the SK channel.",
keywords = "Apamin, Autoradiography, Ca-activated K-channel, Dopaminergic neurons, Electrophysiology, Mouse, Substantia nigra",
author = "X. Gu and Blatz, {A. L.} and German, {D. C.}",
year = "1992",
doi = "10.1016/0361-9230(92)90044-X",
language = "English (US)",
volume = "28",
pages = "435--440",
journal = "Brain Research Bulletin",
issn = "0361-9230",
publisher = "Elsevier Inc.",
number = "3",

}

TY - JOUR

T1 - Subtypes of substantia nigra dopaminergic neurons revealed by apamin

T2 - Autoradiographic and electrophysiological studies

AU - Gu, X.

AU - Blatz, A. L.

AU - German, D. C.

PY - 1992

Y1 - 1992

N2 - In the intact animal, some substantia nigra dopaminergic neurons exhibit regular and some exhibit burst firing patterns. In the in vitro slice preparation, however, all dopaminergic neurons exhibit a nonburst firing pattern. Burst firing patterns are thought to be regulated, in part, by a small conductance calcium-activated potassium channel (SK channels). To test whether SK channels reside within the midbrain dopaminergic cell regions of the mouse, receptor autoradiographic experiments were conducted with the SK channel antagonist, 125I-apamin. To determine whether SK channels play a role in burst firing pattern generation in substantia nigra dopaminergic neurons, changes in firing patterns of these cells were examined in the in vitro slice preparation following apamin superfusion (1-1000 nM). It was demonstrated that a) specific binding of radiolabeled apamin was found within the dopaminergic cell regions of the substantia nigra pars compacta and ventral tegmental area (2.7-4.7 fmol/mg tissue): b) the firing patterns of less than half of the dopaminergic neurons were changed from a regular pattern to that of a burster with concentrations as low as I nM, but the firing patterns of many neurons were not changed by the drug; and c) blockade of the SK channel did not interfere with the inhibitory effects of dopamine on dopaminergic neuronal impulse flow, indicating that the known hyperpolarizing effects mediated by this dopamine receptor are not importantly mediated via the SK channel.

AB - In the intact animal, some substantia nigra dopaminergic neurons exhibit regular and some exhibit burst firing patterns. In the in vitro slice preparation, however, all dopaminergic neurons exhibit a nonburst firing pattern. Burst firing patterns are thought to be regulated, in part, by a small conductance calcium-activated potassium channel (SK channels). To test whether SK channels reside within the midbrain dopaminergic cell regions of the mouse, receptor autoradiographic experiments were conducted with the SK channel antagonist, 125I-apamin. To determine whether SK channels play a role in burst firing pattern generation in substantia nigra dopaminergic neurons, changes in firing patterns of these cells were examined in the in vitro slice preparation following apamin superfusion (1-1000 nM). It was demonstrated that a) specific binding of radiolabeled apamin was found within the dopaminergic cell regions of the substantia nigra pars compacta and ventral tegmental area (2.7-4.7 fmol/mg tissue): b) the firing patterns of less than half of the dopaminergic neurons were changed from a regular pattern to that of a burster with concentrations as low as I nM, but the firing patterns of many neurons were not changed by the drug; and c) blockade of the SK channel did not interfere with the inhibitory effects of dopamine on dopaminergic neuronal impulse flow, indicating that the known hyperpolarizing effects mediated by this dopamine receptor are not importantly mediated via the SK channel.

KW - Apamin

KW - Autoradiography

KW - Ca-activated K-channel

KW - Dopaminergic neurons

KW - Electrophysiology

KW - Mouse

KW - Substantia nigra

UR - http://www.scopus.com/inward/record.url?scp=0026578592&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026578592&partnerID=8YFLogxK

U2 - 10.1016/0361-9230(92)90044-X

DO - 10.1016/0361-9230(92)90044-X

M3 - Article

C2 - 1350500

AN - SCOPUS:0026578592

VL - 28

SP - 435

EP - 440

JO - Brain Research Bulletin

JF - Brain Research Bulletin

SN - 0361-9230

IS - 3

ER -