Sexual dimorphism of GABAA receptor levels in subcortical brain regions of a woodland rodent (Apodemus sylvaticus)

Canonaco, Marcello; Tavolaro, Renata; Facciolo, Rosa Maria; Carelli, Ana Esmeralda; Cagnin, Mara; Cristaldi, M.

doi:10.1016/0361-9230(96)00034-2

Cited by 16 publications

(16 citation statements)

References 48 publications

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“…In the remaining areas that contained small quantities of white matter, such as corticomedial amygdala nucleus (Co-Me), the lateral amygdala nucleus (LAT), the dorsolateral septal nucleus (LSD), the oriens-pyramidalis CA1 layer of the hippocampus (Or-Py), and the ventromedial hypothalamic nucleus (VMN), relatively low percentage increases (19-25%) were reported. Such a relationship is consistent with the recent data obtained for GABA A receptors in some brain nuclei of the striatonigral and of the bed nucleus stria terminalis-hypothalamic-central gray pathways (Canonaco et al, 1996).…”

Section: Resultssupporting

confidence: 89%

“…,0.05) in the male anterior hypothalamic area (AH; although autoradiogram is not shown for this area) and in the female Co-Me. The hypothalamic areas, which produced similar results to those obtained in a previous study (Canonaco et al, 1996), were included for additional comparison purposes to the [ 3 H] MUS binding values of all brain areas examined and, above all, to those of the BDZ receptor system.…”

Section: Quantitative Autoradiography Of [ 3 H] Mus Binding Levelsmentioning

confidence: 98%

“…The forebrain of each mouse was immediately removed, mounted onto a cryostat chuck by using powdered dry ice, and then transferred to a deep freezer (-40°) until an autoradiographic binding assay was performed. Because handling of this murine species could evoke hazardous conditions that could profoundly alter GABAergic binding activities, as shown by the direct effects of the stress-released glucocorticoid derivative (tetrahydrodeoxycorticosterone) on GABA A receptor activity (Majewska, 1992), gonadal and skull morphological features were examined after decapitation (Canonaco et al, 1996). It was during this phase that we were able to ensure that only sexually mature male and nonpregnant mature female mice (more or less 90 days old) were chosen for the autoradiographic study.…”

Section: Animalsmentioning

confidence: 99%

“…Male and female A. sylvaticus between the ages of 2 and 5 months were captured by using Longworth live traps as described in a recent study (Canonaco et al, 1996). These traps were deposited in the surrounding woodland areas of Cosenza, Italy, and inspected every day on a regular basis.…”

Section: Animalsmentioning

confidence: 99%

“…Adjacent coronal sections (16 µm) obtained from male (n 5 5) and female (n 5 5) mice were thawed and preincubated (3 times for 10 minutes each) in 50 mM ice-cold Tris-citrate buffer (pH 7.1; GABA A sites) and in 50 mM ice-cold Tris-HCl buffer (pH 7.4 (Canonaco et al, , 1996 and from preliminary saturation and wipe assays. Another series of adjacent brain sections was also included to determine nonspecific binding value, which proved to be similar to that of background when final concentrations of GABA (100 µM) and of diazepam (10 µM) were added to their respective incubation media.…”

Section: In Vitro Quantitative Autoradiographymentioning

confidence: 99%

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Dimorphic distribution of the two main GABAA binding sites in cortical and limbic areas of a rodent living in natural environmental conditions

1997

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Labeling of the two more important gamma-aminobutyric acidA (GABA(A)) supramolecular sites with [3H] muscimol (GABA(A)) and [3H] flunitrazepam (benzodiazepine) provided saturable, stable, and dimorphic binding activities in cortical and limbic regions of the wood mouse Apodemus sylvaticus. Of the cortical layers, which contained the highest [3H] muscimol binding levels, only the female lamina V supplied a greater (51%; P <0.01) receptor density than in the male. Areas of the limbic system instead proved to be the more favorable targets for differential GABA(A) binding levels. The highest (P <0.001) and higher levels were found in the oriens-pyramidalis CA1 layer of the hippocampus (65%) and in the vertical limb diagonal band-medial septal nucleus (48%), basolateral amygdala nucleus (45%), and ventromedial hypothalamic nucleus (43%), respectively, of the female. A similar pattern was obtained for [3H]flunitrazepam binding activity, especially in the presence of GABA. The highest and higher binding activities were obtained in the female central amygdala nucleus (78%) and in the ventromedial hypothalamic nucleus (52%), basolateral amygdala nucleus (48%), and oriens-pyramidalis CA1 layer of the hippocampus (47%), respectively, whereas higher levels were observed only in the male vertical limb diagonal band-medial septal nucleus (56%). Even in the cortical regions, the female exhibited higher (42%; cortex lamina V) and moderately higher (38%; cortex lamina VI) levels, with binding differences in the latter site plus in the basolateral amygdala nucleus occurring in a GABA-nondependent manner. From the saturation binding analyses it was possible to reveal that both maximal number of binding sites (Bmax) and mean dissociation constant (K(D)) modifications were responsible for receptor differences of the two GABAergic sites. These findings tend to suggest that dimorphic variations of the GABA(A) supramolecular sites, in some cortical and limbic regions, are strongly involved in sex-specific aggressive and reproductive activities of rodents living in their natural habitats.

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Section: Resultssupporting

confidence: 89%

Section: Quantitative Autoradiography Of [ 3 H] Mus Binding Levelsmentioning

confidence: 98%

Section: Animalsmentioning

confidence: 99%

Section: Animalsmentioning

confidence: 99%

Section: In Vitro Quantitative Autoradiographymentioning

confidence: 99%

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Dimorphic distribution of the two main GABAA binding sites in cortical and limbic areas of a rodent living in natural environmental conditions

1997

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Sexual dimorphism and developmental regulation of substantia nigra function

Velı́šková

Moshé

2001

Annals of Neurology

107

103

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The substantia nigra is an important brain nucleus involved in the expression of movement disorders and seizures. The two most common movement disorders affecting the substantia nigra, Parkinson's disease and Tourette syndrome, show gender differences and age-related onset. To assess the substrates for the gender and age specificity of substantia nigra-related disorders, we determined the functional properties of the substantia nigra gamma-aminobutyric acid (GABAA) system along its anterior-posterior axis, using localized microinfusions of muscimol (a GABAA agonist) and susceptibility to motor seizures in rats. In the substantia nigra, there are sex-specific differences in the topographic segregation and functionality of GABAA systems. In mature male rats there are two distinct regions mediating opposite effects on seizures; in female rats there is only one region that can affect seizures. In the neonatal period, the presence of circulating testosterone is essential for the development of a substantia nigra region that exerts proconvulsant effects throughout the rat's life, a unique feature of the male substantia nigra. The final maturation of the substantia nigra occurs in the peripubertal period, and is in part regulated by testosterone as well. The recognition of the existence of distinct sex- and age-specific substantia nigra features can be translated into new cures of disorders affecting the substantia nigra.

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AMPA, kainate, and NMDA receptor densities in the hippocampus of untreated male rats and females in estrus and diestrus

Palomero‐Gallagher

Bidmon²,

Zilles

2003

J of Comparative Neurology

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Steroid hormones systematically affect numerous neuronal targets, thus influencing, in a permanent or a transitory manner, the way the brain reacts to external and internal stimuli. The hippocampus is an important brain region for learning and memory and the glutamatergic intrahippocampal pathway plays a major role in performing such functions. We applied quantitative in vitro receptor autoradiography to examine how the in vivo hormone milieu affects the densities of AMPA, kainate, and NMDA receptors in the hippocampus of adult male rats and females in estrus and diestrus. All three examined receptor types presented significant gender-specific differences in their densities. The hippocampus of male rats contains significantly more AMPA, kainate, and NMDA receptors than that of female rats. Female rats in diestrus have significantly higher AMPA receptor densities than female rats in estrus. AMPA changes occurred to the same extent in CA1-3 and in the dentate gyrus. Significant differences in the densities of NMDA receptors were observed in the CA1-3 regions, whereas kainate receptor differences were restricted to the CA1 region. These results further support that steroid hormones, through their modulation of AMPA and NMDA receptors, may be involved in the control of synaptic efficacy and, therefore, influence learning and memory.

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Sexual dimorphism of GABAA receptor levels in subcortical brain regions of a woodland rodent (Apodemus sylvaticus)

Cited by 16 publications

References 48 publications

Dimorphic distribution of the two main GABAA binding sites in cortical and limbic areas of a rodent living in natural environmental conditions

Dimorphic distribution of the two main GABAA binding sites in cortical and limbic areas of a rodent living in natural environmental conditions

Sexual dimorphism and developmental regulation of substantia nigra function

AMPA, kainate, and NMDA receptor densities in the hippocampus of untreated male rats and females in estrus and diestrus

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