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Amphetamine and cocaine induce different patterns of c‐ fos mRNA expression in the striatum and subthalamic nucleus depending on environmental context
Author(s) -
Uslaner Jason,
Badiani Aldo,
Norton Camille S.,
Day Heidi E. W.,
Watson Stanley J.,
Akil Huda,
Robinson Terry E.
Publication year - 2001
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.0953-816x.2001.01574.x
Subject(s) - amphetamine , striatum , substantia nigra , globus pallidus , dynorphin , neuroscience , context (archaeology) , medium spiny neuron , subthalamic nucleus , population , c fos , immediate early gene , biology , enkephalin , gene expression , basal ganglia , medicine , dopamine , central nervous system , opioid , parkinson's disease , opioid peptide , gene , dopaminergic , genetics , receptor , environmental health , paleontology , disease , deep brain stimulation
In the dorsal striatum, there are two major populations of medium spiny projection neurons. One population is positive for dynorphin mRNA (DYN+), and these cells project preferentially to the substantia nigra, forming the so‐called ‘direct pathway’. A second population is positive for enkephalin mRNA (ENK+), and these cells influence the substantia nigra indirectly, via the globus pallidus and subthalamic nucleus. Psychostimulant drugs, such as amphetamine and cocaine, are reported to induce immediate early genes (IEGs) in only one subpopulation of dorsal striatal projection neurons, DYN+ cells. However, this apparent selectivity appears to be a function of environmental context. We found that when given in the animal's home cage, amphetamine and cocaine increased expression of the IEG, c‐ fos , almost exclusively in DYN+ cells. However, when given in a novel environment, amphetamine and cocaine increased c‐ fos mRNA in both DYN+ and ENK+ cells. Furthermore, amphetamine and cocaine increased c‐ fos mRNA expression in the subthalamic nucleus when administered in the novel environment, but not when given at home. We conclude that the neural circuitry engaged by psychostimulant drugs, and their ability to induce specific patterns of gene expression, are determined by the environmental context in which they are experienced. This may be related to the ability of environmental novelty to facilitate psychostimulant drug‐induced neuroplasticity.