Search

Your search keyword '"Casas, Sebastián"' showing total 2 results
Start Over Author "Casas, Sebastián" Topic allopregnanolone
2 results on '"Casas, Sebastián"'

1. Puberty and neurosteroids: Effect of allopregnanolone on gaba glutamate release and differential hypothalamic expression and activity of 3α-hor in female rats

Author

Giuliani, Fernando Alfredo, Escudero, Carla Gimena, Casas, Sebastián Marcelo, Bazzocchini, Vanesa Silvana, Yunes, Roberto Miguel Federico, Laconi, Myriam Raquel, and Cabrera Kreiker, Ricardo Jorge

Subjects
Medicina Básica, CIENCIAS MÉDICAS Y DE LA SALUD, GABA RELEASE, PUBERTY, ALLOPREGNANOLONE, Neurociencias, GLUTAMATE RELEASE
Abstract

The hypothalamic release of glutamate and GABA regulates neurosecretory functions that may control the onset of puberty. This release may be influenced by neurosteroids such as allopregnanolone. Using superfusion experiments we examined the role of allopregnanolone on the K+-evoked and basal [3H]-glutamate and [3H]-GABA release from mediobasal hypothalamus and anterior preoptic area in prepubertal, vaginal opening and pubertal (P) rats and evaluated its modulatory effect on GABAA and NMDA (N-methyl-D-aspartic acid) receptors. Also, we examined the hypothalamic activity and mRNA expression of 3ahydroxysteroid oxidoreductase (3a-HSOR) – enzyme that synthesizes allopregnanolone – using a spectrophotometric method and RT-PCR, respectively. Allopregnanolone increased both the K+-evoked [3H]-glutamate and [3H]-GABA release in P rats, being the former effect mediated by the modulation of NMDA receptors – as was reverted by Mg2+ and by the NMDA receptor antagonist AP-7 and the latter by the modulation of NMDA and GABAA receptors – as was reverted by Mg2+ and the GABAA receptor antagonist bicuculline. The neurosteroid also increased the basal release of [3H]-glutamate in VO rats in an effect that was dependent on the modulation of NMDA receptors as was reverted by Mg2+. On the other hand we show that allopregnanolone reduced the basal release of [3H]-GABA in P rats although we cannot elucidate the precise mechanism bywhich the neurosteroid exerted this latter effect. The enzymatic activity and the mRNA expression of 3a-HSOR were both increased in P rats regarding the other two studied stages of sexual development. These results suggest an important physiological function of allopregnanolone in the hypothalamus of the P rat where it might be involved in the ‘fine tuning’ of neurosecretory functions related to the biology of reproduction of the female rats. Fil: Giuliani, Fernando Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Fil: Escudero, Carla Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Fil: Casas, Sebastián Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Fil: Bazzocchini, Vanesa Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Fil: Yunes, Roberto Miguel Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de Farmacología; Argentina; Fil: Laconi, Myriam Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina; Fil: Cabrera Kreiker, Ricardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina

Published
2013

2. Allopregnanolone prevents memory impairment: Effect on mRNA expression and enzymatic activity of hippocampal 3-α hydroxysteroid oxide-reductase

Author

Escudero, Carla, Casas, Sebastián, Giuliani, Fernando, Bazzocchini, Vanesa, García, Sebastián, Yunes, Roberto, and Cabrera, Ricardo

Subjects
*PREGNANOLONE, *MESSENGER RNA, *HIPPOCAMPUS (Brain), *MEMORY disorders, *REDUCTASES, *GENE expression, *PREVENTION
Abstract

Abstract: In this work we investigated how the neurosteroid allopregnanolone can modulate learning and memory processes. For this purpose, we used ovariectomized (OVX) rats subcutaneously injected with oestradiol benzoate (E) alone or E and progesterone (P). Then, rats were injected in dorsal hippocampus with allopregnanolone or vehicle. Animals were tested in inhibitory avoidance task (IA task). After behavioural test hippocampal mRNA expression and enzymatic activity of 3α-HOR, the enzyme responsible of allopregnanolone synthesis, were analysed. In IA task OVX-EP rats spent less time on platform, compared to those OVX or OVX-E. Regression analyses revealed that there was a significant negative relationship between E-P infusion and performance in this task. Pre-training allopregnanolone administration to OVX-EP rats increased the time spent on the platform. Interestingly, when enzymatic activity of 3α-HOR was tested, OVX-EP rats showed a significant decrease in the enzymatic activity, compared with OVX and OVX-E rats. In addition, OVX-EP group showed a significant increase in the enzymatic activity after intrahippocampal infusion of allopregnanolone. On the other hand, when mRNA expression of 3α-HOR was analysed no differences were observed when the hippocampal allopregnanolone injection was done. These results suggest that E and P have amnesic effects on female rats, being reversed by allopregnanolone through its modulation on hippocampal 3α-HOR activity. [Copyright &y& Elsevier]

Published
2012
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results