Adrenalectomy modifies the hippocampal 5-HT(1A) receptors and the anxiolytic-like effect of 8-OH-DPAT in rats.
Stress is closely related with levels of corticosteroid and corticotrophin releasing factor, which at the same time can modify 5-HT(1A) receptors and brain serotonin levels. Consequently, the absence of corticosteroids in rats induced by an adrenalectomy could be useful to understand the functionality of the brain serotonergic system after a stressing event. The influence of 15 min of forced swimming was explored on sham and adrenalectomized rats by measuring the 5-HT(1A) receptor density in raphe and hippocampus. Other previously stressed groups (sham and adrenalectomized) were tested in two anxiety models with the 5-HT(1A) agonist 8-OH-DPAT, the postsynaptic antagonist MM-77, and with a combination of these two compounds. It was found that the removal of adrenals in rats that were not previously stressed induced an increase in the postsynaptic 5-HT(1A) receptor density. On the other hand, an adrenalectomy in rats that were previously stressed induced a reduction in the same receptor density. Adrenal gland removal induced an anxiolytic-like effect. However, after the injection of 8-OH-DPAT, adrenalectomized rats showed anxiogenic-like actions, an effect which was reversed by MM-77. Data show that changes in 5-HT(1A) receptors density caused by a stressful session can have behavioral consequences, thus emphasizing the need to reconsider the clinical use of 5-HT(1A) ligands after traumatic events.
Briones-Aranda
Alfredo
A
Facultad de Medicina Humana, UNACH, Tuxtla Gutiérrez Chiapas, Mexico. alfred725@hotmail.com
Castillo-Salazar
Mariano
M
Picazo
Ofir
O
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000315:Adrenalectomy; D000818:Animals; D014151:Anti-Anxiety Agents; D001007:Anxiety / Q000523:psychology; D001345:Autoradiography; D006624:Hippocampus / Q000378:metabolism* / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D044282:Receptor, Serotonin, 5-HT1A / Q000502:physiology*; D058829:Serotonin 5-HT1 Receptor Antagonists; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013315:Stress, Psychological / Q000523:psychology; D013388:Succinimides / Q000494:pharmacology; D013550:Swimming / Q000523:psychology
D014151:Anti-Anxiety Agents; C413583:MM 77; D010879:Piperazines; D058829:Serotonin 5-HT1 Receptor Antagonists; D017366:Serotonin Receptor Agonists; D013388:Succinimides; D044282:Receptor, Serotonin, 5-HT1A; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin