Acute stress and nicotine cues interact to unveil locomotor arousal and activity-dependent gene expression in the prefrontal cortex.
BACKGROUND
This study examines the interactive effects of acute stress and nicotine-associated contextual cues on locomotor activity and activity-dependent gene expression in subregions of the prefrontal cortex.


METHODS
Locomotor activity of rats was measured in a context associated with either low-dose nicotine or saline administration with or without 5 minutes of pre-exposure to ferrets, a nonphysical stressor. After 45 minutes in the test environment, plasma corticosterone levels and mRNA levels of the immediate-early genes Arc, NGFI-B, and c-Fos in prefrontal and primary motor cortical subregions were measured.


RESULTS
Stress alone increased plasma corticosterone and prefrontal cortex gene expression. Low-dose nicotine cues had no effect on corticosterone levels nor did they elicit conditioned motor activation, and they caused minor elevations in gene expression. Stress and low-dose nicotine cues, however, interacted to elicit conditioned motor activation and further increases in early response gene expression in prefrontal but not in the primary motor cortical subregions.


CONCLUSIONS
Stress interacts with nicotine-associated cues to uncover locomotor arousal, a state associated with prefrontal neuronal activation and immediate early gene expression. Thus, in nicotine-experienced individuals, stress may be an important determinant of subjective reactivity and prefrontal cortex activation that occurs in response to nicotine-associated cues.
Schiltz
Craig A
CA
Neuroscience Training Program, University of Wisconsin-Madison Medical School, Madison, Wisconsin 53719, USA.
Kelley
Ann E
AE
Landry
Charles F
CF
D000386:AIDS-Related Complex / Q000235:genetics / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003345:Corticosterone / Q000097:blood; D003463:Cues; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects* / Q000502:physiology; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000378:metabolism* / Q000503:physiopathology*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D018722:Nicotinic Agonists; C539820:Nr4a1 protein, rat; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D016760:Proto-Oncogene Proteins c-fos; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D009538:Nicotine; D003345:Corticosterone