Effects of chronic restraint stress and estradiol replacement on glutamate release and uptake in the spinal cord from ovariectomized female rats.
Glutamate is an excitatory neurotransmitter involved in neuronal plasticity and neurotoxicity. Chronic stress produces several physiological changes on the spinal cord, many of them presenting sex-specific differences, which probably involve glutamatergic system alterations. The aim of the present study was to verify possible effects of exposure to chronic restraint stress and 17beta-estradiol replacement on [3H]-glutamate release and uptake in spinal cord synaptosomes of ovariectomized (OVX) rats. Female rats were subjected to OVX, and half of the animals received estradiol replacement. Animals were subdivided in controls and chronically stressed. Restraint stress or estradiol had no effect on [3H]-glutamate release. The chronic restraint stress promoted a decrease and 17beta-estradiol induced an increase on [3H]-glutamate uptake, but the uptake observed in the restraint stress +17beta-estradiol group was similar to control. Furthermore, 17beta-estradiol treatment caused a significant increase in the immunocontent of the three glutamate transporters present in spinal cord. Restraint stress had no effect on the expression of these transporters, but prevented the 17beta-estradiol effect. We suggest that changes in the glutamatergic system are likely to take part in the mechanisms involved in spinal cord plasticity following repeated stress exposure, and that 17beta-estradiol levels may affect chronic stress effects in this structure.
Crema
Leonardo Machado
LM
Programa de Pós-Graduação em Neurociências, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Vendite
Deusa
D
Horn
Ana Paula
AP
Diehl
Luisa Amalia
LA
Aguiar
Ana Paula
AP
Nunes
Edelvan
E
Vinade
Lúcia
L
Fontella
Fernanda Urruth
FU
Salbego
Christianne
C
Dalmaz
Carla
C
D000818:Animals; D002908:Chronic Disease; D004958:Estradiol / Q000494:pharmacology*; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism; D050580:Excitatory Amino Acid Transporter 3 / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism
D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; C493392:Slc1a3 protein, rat; D018698:Glutamic Acid; D004958:Estradiol