Antidepressant treatment reduces Fos-like immunoreactivity induced by swim stress in different columns of the periaqueductal gray matter.
Antidepressant treatment attenuates behavioral changes induced by uncontrollable stress. The periaqueductal gray matter (PAG) is proposed to be a brain site involved in the behavioral responses to uncontrollable stress and antidepressant effects. The main goal of the present study was to investigate the effect of antidepressant treatment on the pattern of neural activation of the PAG along its mediolateral and rostrocaudal subregions after a forced swim stress episode. Male Wistar rats were sub-acutely treated with desipramine (a selective noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) or clomipramine (a non-selective serotonin and noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) and submitted to the forced swimming test (FST). Two hours after the test their brain were removed for Fos immunohistochemistry. Fos-like immunoreactivity (FLI) in rostral, intermediate and caudal portions of dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG) PAG were quantified by a computerized system. The FST session increased FLI in most parts of the PAG. Previous treatment with desipramine or clomipramine reduced FLI in all columns of the PAG. FLI in the PAG correlated positively with to the immobility time and negatively with to climbing behavior scored during the test. These results indicate that neurons in the PAG are activated by uncontrollable stress. Moreover, inhibitory action of antidepressants on this activity may be associated with the anti-immobility effects of these drugs in the FST.
Lino-de-Oliveira
Cilene
C
Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas (CCB), Universidade Federal de Santa Catarina (UFSC), Campus Trindade, 88040-900 Florianópolis, SC, Brazil. cilene@ccb.ufsc.br
de Oliveira
Rúbia M W
RM
Pádua Carobrez
Antonio
A
de Lima
Thereza C M
TC
del Bel
Elaine Aparecida
EA
Guimarães
Francisco Silveira
FS
D000704:Analysis of Variance; D000818:Animals; D000928:Antidepressive Agents / Q000627:therapeutic use*; D002452:Cell Count / Q000379:methods; D002997:Clomipramine / Q000627:therapeutic use*; D003891:Desipramine / Q000627:therapeutic use*; D004195:Disease Models, Animal; D046353:Immobility Response, Tonic / Q000187:drug effects; D008297:Male; D016761:Oncogene Proteins v-fos / Q000378:metabolism*; D010487:Periaqueductal Gray / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000188:drug therapy* / Q000209:etiology; D013550:Swimming / Q000523:psychology
D000928:Antidepressive Agents; D016761:Oncogene Proteins v-fos; D002997:Clomipramine; D003891:Desipramine