Regulation of hippocampal 5-HT1A receptor gene expression by dexamethasone.
The effect of dexamethasone, a selective GR agonist, on hippocampal, 5-HT1A receptor mRNA expression and 5-HT1A binding was examined using in situ hybridization histochemistry and in vitro receptor autoradiography. One week after adrenalectomy, both 5-HT1A receptor mRNA expression and 5-HT1A binding were increased throughout the hippocampus. Administration of dexamethasone at the time of adrenalectomy significantly attenuated the increases in 5-HT1A mRNA expression in all hippocampal subfields (p < .05, Fisher Test), although 5-HT1A mRNA levels remained significantly higher than sham levels in all subfields with the exception of CA1. However, 5-HT1A binding levels were responsive to dexamethasone administration only within particular hippocampal subfields, CA1, and dentate gyrus. We conclude that GR occupation negatively regulates 5-HT1A receptor mRNA expression within the hippocampus and that 5-HT1A receptor sites are most sensitive to modulation in those hippocampal subfields expressing higher levels of GR receptors.
Chalmers
D T
DT
Mental Health Research Institute, University of Michigan, Ann Arbor 48109.
López
J F
JF
Vázquez
D M
DM
Akil
H
H
Watson
S J
SJ
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001345:Autoradiography; D003345:Corticosterone / Q000097:blood; D003720:Densitometry; D003907:Dexamethasone / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D006624:Hippocampus / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D017403:In Situ Hybridization; D008024:Ligands; D008297:Male; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000378:metabolism*
D008024:Ligands; D015347:RNA Probes; D012333:RNA, Messenger; D011985:Receptors, Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone