Pallidal control of substantia nigra dopaminergic neuron firing pattern and its relation to extracellular neostriatal dopamine levels.

Full Abstract

The firing patterns of dopaminergic neurons in vivo are strongly modulated by afferent input. The principal GABAergic inputs to the dopaminergic neurons of the substantia nigra originate from neurons of the neostriatum, globus pallidus and substantia nigra pars reticulata. It has previously been shown that the firing pattern of nigral dopaminergic neurons can be manipulated by pharmacologically induced excitation or inhibition of the globus pallidus with relatively little effect on firing rate. We used this technique to explore the relation between the firing pattern of dopaminergic neurons and extracellular dopamine levels in the neostriatum in vivo. Specifically, we tested whether an increase in burst firing in dopaminergic neurons produced by increased pallidal activity led to increased extracellular dopamine levels in the neostriatum. Single unit extracellular recording combined with simultaneous microdialysis was used to measure the firing rates and patterns of dopaminergic neurons and extracellular striatal dopamine levels, respectively, during bicuculline-induced excitation of the globus pallidus. Pallidal excitation resulted in a marked increase in burst firing in dopaminergic neurons along with only a slight increase in firing rate, but produced a significant elevation (approximately 45%) in neostriatal dopamine levels. These data suggest that afferent-induced burst firing in dopaminergic neurons leads to an increase in extracellular dopamine levels in the neostriatum when compared with less bursty patterns with similar overall firing rates.

Author information

Author/s: Lee, C R (CR); Abercrombie, E D (ED); Tepper, J M (JM);

Affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA.

Grants: NS19608 (Agency:NINDS NIH HHS) ; NS34865 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.

Journal: Neuroscience (Neuroscience), published in United States. (Language: eng)

Reference: 2004-; vol 129 (issue 2) : pp 481-9

Dates: Created 2004/10/25; Completed 2005/01/13; Revised 2007/11/14;

PMID: 15501605, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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