Absence seizures during pregnancy in WAG/Rij rats

Tolmacheva, E.A.; Chepurnov, S.A.; Chepurnova, N.E.; Kochetkov, Yakov; Luijtelaar, Gilles van

doi:10.1016/j.physbeh.2004.02.028

Cited by 16 publications

(8 citation statements)

References 26 publications

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“…No changes in SWDs were found after acute administration of estrogen [5]. However, in contrast, we found that chronic elevation of progesterone during pregnancy was accompanied by a decrease in the number of SWDs in WAG/Rij rats [8]. Rats of the WAG/Rij strain are considered to be one of the well-validated models of absence epilepsy and their seizures originate in the cortico-thalamo-cortical network [10,11].…”

Section: Introductionmentioning

confidence: 60%

“…Virtually, a number of adaptive changes in specific binding associated with GABA A receptors as well as in density of dopamine receptors was indeed observed following ovariectomy in different brain structures such as striatum and prefrontal cortex [24,25]. The lack of any changes in the basal occurrence of SWDs in OVX females raises doubts whether and in which way ovarian steroids play a role in the regulation of SWDs under resting conditions [5][6][7][8].…”

Section: Discussionmentioning

confidence: 99%

“…Rats of the WAG/Rij strain are considered to be one of the well-validated models of absence epilepsy and their seizures originate in the cortico-thalamo-cortical network [10,11]. It is suggested that a number of adaptive changes in the system, such as tolerance, as well as possible genomic effects of ovarian steroids, which can take place during pregnancy, may account for this contradiction and explain this decrease in the occurrence of absence seizures [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The role of ovarian steroid hormones in the regulation of basal and stress induced absence seizures

Tolmacheva

Luijtelaar

2007

The Journal of Steroid Biochemistry and Molecular Biology

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Section: Introductionmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The role of ovarian steroid hormones in the regulation of basal and stress induced absence seizures

Tolmacheva

Luijtelaar

2007

The Journal of Steroid Biochemistry and Molecular Biology

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“…Although it is classically thought that the ratio of estradiol/progesterone is the crucial factor for determining the occurrence of seizures (Bäckström, 1977), no such relationship between this ratio and SWD could be found in these pregnant rats. These data suggest an inverse relationship between progesterone and SWDs during pregnancy (Tolmacheva et al, 2004). …”

Section: Role Of Sex Hormones On Absence Epilepsy and Seizuresmentioning

confidence: 76%

Animal models of absence epilepsies: What do they model and do sex and sex hormones matter?

Luijtelaar

Onat

Gallagher

2014

Neurobiology of Disease

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While epidemiological data suggest a female prevalence in human childhood- and adolescence-onset typical absence epilepsy syndromes, the sex difference is less clear in adult-onset syndromes. In addition, although there are more females than males diagnosed with typical absence epilepsy syndromes, there is a paucity of studies on sex differences in seizure frequency and semiology in patients diagnosed with any absence epilepsy syndrome. Moreover, it is unknown if there are sex differences in the prevalence or expression of atypical absence epilepsy syndromes. Surprisingly, most studies of animal models of absence epilepsy either did not investigate sex differences, or failed to find sex-dependent effects. However, various rodent models for atypical syndromes such as the AY9944 model (prepubertal females show a higher incidence than prepubertal males), BN model also with a higher prevalence in males and the Gabra1 deletion mouse in the C57BL/6J strain offer unique possibilities for the investigation of the mechanisms involved in sex differences. Although the mechanistic bases for the sex differences in humans or these three models are not yet known, studies of the effects of sex hormones on seizures have offered some possibilities. The sex hormones progesterone, estradiol and testosterone exert diametrically opposite effects in genetic absence epilepsy and pharmacologically-evoked convulsive types of epilepsy models. In addition, acute pharmacological effects of progesterone on absence seizures during proestrus are opposite to those seen during pregnancy. 17β-Estradiol has anti-absence seizure effects, but it is only active in atypical absence models. It is speculated that the pro-absence action of progesterone, and perhaps also the delayed pro-absence action of testosterone, are mediated through the neurosteroid allopregnanolone and its structural and functional homolog, androstanediol. These two steroids increase extrasynaptic thalamic tonic GABAergic inhibition by selectively targeting neurosteroid-selective subunits of GABAA receptors (GABAARs). Neurosteroids also modulate the expression of GABAAR containing the γ2, α4, and δ subunits. It is hypothesized that differences in subunit expression during pregnancy and ovarian cycle contribute to the opposite effects of progesterone in these two hormonal states.

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“…The observation that ethanol clearance is elevated to the same degree throughout pregnancy in the current study is consistent with a role for progesterone rather than estradiol in the pregnancy effect. It has been shown that in the rat, plasma progesterone levels are sharply elevated throughout gestation and only decline at parturition, while plasma estradiol is low early in pregnancy and reaches a maximum on gestational day 18-20 (Escalada et al, 1996;Tolmacheva et al, 2004).…”

Section: Discussionmentioning

confidence: 99%