Hippocampal serotonergic system is involved in anxiety-like behavior induced by corticotropin-releasing factor.
To clarify the interaction between anxiety-like behavior produced by corticotropin-releasing factor (CRF) and the 5-HT system, we investigated the effects of intracerebroventricular (i.c.v.) administration of CRF on an elevated plus-maze performance as indices of anxiety, measuring extracellular levels of 5-HT in the ventral hippocampus using an in vivo brain dialysis method in rats. The time spent in the open arms of the maze and the number of open arm entries were decreased in a dose-dependent manner by the administration of CRF (0.3-1.0 microg/rat). These effects of CRF were prevented by pretreatment with a 5-HT(1A) receptor agonist, 8-OH-DPAT (0.5 mg/kg, s.c.). In biochemical studies, CRF increased 5-HT release about 150-250% above baseline in the ventral hippocampus and this elevation was significantly inhibited by a CRF receptor antagonist, alpha-Helical CRF(9-41) (50 mug/rat), and 5-HT(1A) receptor agonist, 8-OH-DPAT (0.5 mg/kg, s.c.). These results suggested that the anxiety-like effect produced by CRF may have involved increased 5-HT transmission in the ventral hippocampus. Taken with the evidence for hypersecretion of CRF in patients with depression and anxiety-related disorders, our findings lead to the intriguing hypothesis that interaction between CRF and 5-HT, especially in the ventral hippocampus, plays a role in the etiology of affective and anxiety disorders.
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582, Japan.
Yoshifumi
Y
Kagamiishi
Tsuneyuki
T
Yamamoto
Shigenori
S
Watanabe
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001007:Anxiety / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D007276:Injections, Intraventricular; D008297:Male; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D012701:Serotonin / Q000032:analysis / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D018019:Receptors, Corticotropin-Releasing Hormone; D017366:Serotonin Receptor Agonists; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003346:Corticotropin-Releasing Hormone