Both phasic sensory stimulation and tonic pharmacological activation increase Fos-like immunoreactivity in the rat locus coeruleus.
Neuronal activation increases levels of Fos protein, the product of the early immediate gene c-fos. Since most studies used stimuli that evoke sustained elevations in activity; the present study examined Fos-like immunoreactivity (Fos-LI) in the nucleus locus coeruleus (LC). Halothane-anesthetized rats were given either footshock to elicit phasic activation of LC neurons or yohimbine (10 mg/kg, i.p.) to induce a tonic increase in firing. Both treatments markedly increased Fos-LI in a subpopulation of LC neurons. These results demonstrate that c-fos induction does not require high tonic levels of neuronal activity and that Fos-LI may underestimate the proportion of LC neurons neurophysiologically activated by a given stimulus and suggest that factors beyond neuronal activity per se contributes to c-fos expression.
Grant
S J
SJ
Department of Psychology, University of Delaware, Newark 19716.
Bittman
K
K
Benno
R H
RH
D000818:Animals; D004597:Electroshock; D007150:Immunohistochemistry; D008125:Locus Coeruleus / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012677:Sensation / Q000502:physiology*; D013268:Stimulation, Chemical; D015016:Yohimbine / Q000494:pharmacology
D016760:Proto-Oncogene Proteins c-fos; D015016:Yohimbine