5-HT1A receptor activation counteracts c-Fos immunoreactivity induced in serotonin neurons of the raphe nuclei after immobilization stress in the male rat.
The serotoninergic system and the 5-HT1A receptors have been involved in the brain response to acute stress. The aim of our study was evaluate the role of the 5-HT1A receptors in serotoninergic cells of rostral and caudal raphe nuclei under acute immobilization in rats. Double immunocytochemical staining of 5-hydroxy-tryptamine and c-Fos protein and stereology techniques were used to study the specific cell activation in the raphe nuclei neurons in five groups (control group, immobilization group (immobilization lasting 1 h), DPAT group (8-OH-DPAT 0.3 mg/kg, s.c.), DPAT+IMMO group (8-OH-DPAT 0.3 mg/kg, s.c., 30' prior acute immobilization) and WAY+DPAT+IMMO group (WAY-100635 0.3 mg/kg, s.c. and 8-OH-DPAT 0.3 mg/kg, s.c., 45' and 30', respectively, before immobilization). Our results showed an increase in the number of c-Fos immunoreactive nuclei in serotoninergic cells in both dorsal and median raphe nuclei in the immobilized group. The 8-OH-DPAT pretreatment counteracted the excitatory effects of the acute immobilization in these brain regions. In addition, WAY-100635 administration reduced the effect of 8-OH-DPAT injection, suggesting a selective 5-HT1A receptor role. Raphe pallidus and raphe obscurus did not show any differences among experimental groups. We suggest that somatodendritic 5-HT1A receptors in rostral raphe nuclei may play a crucial role in both mediating the consequences of uncontrollable stress and the possible beneficial effects of treatment with 5-HT1A receptor agonists.
Rioja
José
J
Department of Human Physiology, School of Medicine, Campus de Teatinos, Boulevard Louis Pasteur, 32, University of Malaga, 29071 Malaga, Spain.
Santín
Luis J
LJ
Doña
Alicia
A
de Pablos
Laura
L
Minano
Francisco J
FJ
Gonzalez-Baron
Salvador
S
Aguirre
Jose A
JA
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D007103:Immobilization; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011903:Raphe Nuclei / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D058825:Serotonin 5-HT1 Receptor Agonists; D058829:Serotonin 5-HT1 Receptor Antagonists; D013315:Stress, Psychological / Q000378:metabolism*
D010879:Piperazines; D016760:Proto-Oncogene Proteins c-fos; D011725:Pyridines; D058825:Serotonin 5-HT1 Receptor Agonists; D058829:Serotonin 5-HT1 Receptor Antagonists; D012701:Serotonin; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin