Increase of 5-HT7 (serotonin-7) and 5-HT1A (serotonin-1A) receptor mRNA expression in rat hippocampus after adrenalectomy.
The brain 5-HT (serotonin) system and circulating corticosteroids are in close interaction and both are implicated in the pathogenesis of affective disorders. The 5-HT1A receptor is thought to play a major role in this relationship. However, the recently cloned 5-HT7 receptor may also be involved, given its pharmacological similarities to the 5-HT1A receptor and its high expression in corticolimbic structures. Using in situ hybridization histochemistry, we have investigated 5-HT7 and 5-HT1A receptor mRNA expression in selected areas of the rat brain 7 days post-adrenalectomy. 5-HT7 receptor mRNA was increased in CA1 and CA3b after adrenalectomy, with no alterations in other hippocampal subfields or in retrosplenial cortex. Adrenalectomy was associated with a marked increase of 5-HT1A receptor mRNA in dentate gyrus, CA3 and CA2, but not in CA1, nor in the raphe. These data indicate that circulating adrenal steroids have a inhibitory role on the expression of hippocampal 5-HT7 receptors as well as 5-HT1A receptors, but the effect upon the two transcripts occurs in different subfields. The 5-HT7 receptor is an additional candidate for mediating the interactions between 5-HT and corticosteroids within the hippocampus.
Le Corre
S
S
University Department of Neuropathology, Radcliffe Infirmary, Oxford, UK.
Sharp
T
T
Young
A H
AH
Harrison
P J
PJ
D000305:Adrenal Cortex Hormones / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D006624:Hippocampus / Q000378:metabolism*; D006651:Histocytochemistry; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D017403:In Situ Hybridization; D008297:Male; D010913:Pituitary-Adrenal System / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D011903:Raphe Nuclei / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D044263:Receptors, Serotonin, 5-HT1
D000305:Adrenal Cortex Hormones; D012333:RNA, Messenger; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; C104425:serotonin 7 receptor