Nigrostriatal lesion alters neurophysiological responses to selective and nonselective D-1 and D-2 dopamine agonists in rat globus pallidus

Synapse ◽  
1990 ◽  
Vol 5 (2) ◽  
pp. 83-93 ◽  
Author(s):  
Joanne H. Carlson ◽  
Debra A. Bergstrom ◽  
Susan D. Demo ◽  
Judith R. Walters
Keyword(s):  
Globus Pallidus ◽  
Dopamine Agonists ◽  
Nigrostriatal Lesion

Nigrostriatal Lesion and Dopamine Agonists Affect Firing Patterns of Rodent Entopeduncular Nucleus Neurons

2002 ◽  
Vol 88 (1) ◽  
pp. 487-496 ◽  
Author(s):  
David N. Ruskin ◽  
Debra A. Bergstrom ◽  
Judith R. Walters
Keyword(s):  
Firing Rate ◽  
Globus Pallidus ◽  
Dopamine Agonists ◽  
Interspike Interval ◽  
Skf 38393 ◽  
Substantia Nigra Pars Reticulata ◽  
Entopeduncular Nucleus ◽  
Midbrain Dopamine ◽  
Nigrostriatal Lesion ◽  
Globus Pallidus Internal

Altered activity of the entopeduncular nucleus, the rodent homologue of the globus pallidus internal segment in primates, is thought to mediate behavioral consequences of midbrain dopamine depletion in rodents. Few studies, however, have examined dopaminergic modulation of spiking activity in this nucleus. This study characterizes changes in entopeduncular neuronal activity after nigrostriatal dopaminergic lesion and the effects of systemic treatment with selective D1(SKF 38393) and D2 (quinpirole) agonists in lesioned rats. Extracellular single-unit recordings were performed in awake immobilized rats, either in neurologically intact animals ( n = 42) or in animals that had received unilateral 6-hydroxydopamine infusion into the medial forebrain bundle several weeks previously ( n = 35). Nigrostriatal lesion altered baseline activity of entopeduncular neurons in several ways. Interspike interval distributions had significantly decreased modes and significantly increased coefficient of variation, skewness and kurtosis; yet interspike interval mean (the inverse of firing rate) was not affected. Also, spectral analysis of autocorrelograms indicated that lesion significantly reduced the incidence of regular-spiking neurons and increased the incidence of neurons with 4–18 Hz oscillations. Dopamine agonist treatment reversed some lesion-induced effects: quinpirole reversed changes in interspike interval distribution mode and coefficient of variation, while combined quinpirole and SKF 38393 blocked the appearance of 4–18 Hz oscillations. However, no agonist treatment normalized all aspects of entopeduncular activity. Additionally, inhibition of firing rates by D1 or combined D1/D2 receptor activation indicated that dopamine agonists affected the overall level of entopeduncular activity in a manner similar to that found in the substantia nigra pars reticulata and globus pallidus internal segment after dopamine neuron lesion. These data demonstrate that lesion of the nigrostriatal tract leads to modifications of several aspects of firing pattern in the rodent entopeduncular nucleus and so expand on similar findings in the rodent substantia nigra pars reticulata and in the globus pallidus internal segment in humans and nonhuman primates. The results support the view that dysfunction in the basal ganglia after midbrain dopamine neuron loss relates more consistently to abnormal activity patterns than to net changes in firing rate in the basal ganglia output nuclei, while overall decreases in firing rate in these structures may play a more important role in adverse motor reactions to dopamine agonist treatments.

Opposite rotation induced by dopamine agonists in rats with unilateral lesions of the globus pallidus or substantia nigra

1998 ◽  
Vol 92 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Spyridon Konitsiotis ◽  
Evangelos Kafetzopoulos ◽  
Dimitrios Anastasopoulos ◽  
Pierre J Blanchet
Keyword(s):  
Substantia Nigra ◽  
Globus Pallidus ◽  
Dopamine Agonists
Sign in / Sign up

Export Citation Format

Share Document