Electrocortical Activation by Estrogens

Logothetis, John; Harner, Richard N.

doi:10.1001/archneur.1960.00450030068007

Cited by 90 publications

(49 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This perspective is based on studies beginning in the 1950s, in both laboratory animals and women with epilepsy, showing that estrogens can exacerbate seizures while progestins decrease seizure frequency (Backstrom, 1976;Logothetis and Harner, 1960;Logothetis et al, 1959;Terasawa and Timiras, 1968). Subsequent work, however, has shown that proconvulsant effects of estrogen, as well as anticonvulsant effects of progesterone, may depend to a large extent on the specific experimental conditions used.…”

Section: Introductionmentioning

confidence: 99%

Seizure susceptibility in intact and ovariectomized female rats treated with the convulsant pilocarpine

Scharfman

Goodman

Rigoulot

et al. 2005

Experimental Neurology

View full text Add to dashboard Cite

Despite numerous neuroendocrinological studies of seizures, the influence of estrogen and progesterone on seizures and epilepsy remains unclear. This may be due to the fact that previous studies have not systematically compared distinct endocrine conditions and included all relevant controls. The goal of the present study was to conduct such a study using pilocarpine as chemoconvulsant. Thus, age and weight-matched, intact or ovariectomized rats were tested to determine incidence of status epilepticus and to study events leading to status. Intact female rats were sampled at each cycle stage (proestrus, estrus, metestrus, or diestrus 2). Convulsant was administered at the same time of day, 10:00-10:30 a.m. Statistical analysis showed that there was a significantly lower incidence of status on the morning of estrus, but differences were attenuated in older animals. Ovariectomized rats were distinct in their rapid progression to status. These results show that the incidence of status in female rats following pilocarpine injection, and the progression to pilocarpineinduced status, are influenced by reproductive state as well as age. The hormonal milieu present specifically on the morning of estrus appears to decrease susceptibility to pilocarpine-induced status, particularly at young ages. In contrast, the chronic absence of reproductive steroids that characterizes the ovariectomized rat leads to a more rapid progression to status. This dissociation between incidence vs. progression provides new insight into the influence of estrogen and progesterone on seizures.

show abstract

Section: Introductionmentioning

confidence: 99%

Seizure susceptibility in intact and ovariectomized female rats treated with the convulsant pilocarpine

Scharfman

Goodman

Rigoulot

et al. 2005

Experimental Neurology

View full text Add to dashboard Cite

show abstract

“…It increases neuronal metabolism and discharge rates (5,6). It pro-motes kindling (7,8) and animal experimental (9), as well as clinical (10) seizure occurrence. Progesterone metabolites such as allopregnanolone, in contrast, are potent barbiturate-like ligands at the GABA-chloride ionophore (1 1).…”

mentioning

confidence: 97%

Three Patterns of Catamenial Epilepsy

1997

View full text Add to dashboard Cite

Summary:Purpose: On the basis of the neuroactive properties of estradiol and progesterone and the menstrually related cyclic variations of their serum concentrations, we propose the existence of three hormonally based patterns of seizure exacerbation. Because previous reports both support and refute the concept of catamenial epilepsy, we test the hypothesis by charting seizures and menses and measuring midluteal serum progesterone levels to estimate the frequency of epileptic women with catamenial seizure exacerbation.Methods: One hundred eighty-four women with intractable complex partial seizures (CPS) charted their seizure occurrence and onset of menstruation on a calendar for one cycle during which they had a midluteal blood sample taken for serum progesterone determination on day 22. Levels >5 ng/ml were considered ovulatory. The cycle was divided into four phases with onset of menstruation being day 1: menstrual (M) = -3 to +3, follicular (F) = 4 to 9, ovulatory (0) = 10 to -13, and luteal (L) = -12 to -4. Average daily seizure frequency for each phase was calculated and compared among phases by repeatedmeasures analysis of variance (ANOVA) and the StudentNewman-Keul's test, separately for ovulatory and anovulatory cycles.Results We propose the existence of three hormonally based patterns of seizure exacerbation in epilepsy (1). Seizures do not occur randomly in most men and women with epilepsy (2). They tend to cluster in >50% of cases (2). Seizure clusters in turn may occur with temporal rhythmicity in a significant proportion of men (29%) and women (35%) with epilepsy (3). In women, seizures may cluster in relation to the menstrual cycle; such seizures are commonly termed catamenial epilepsy (4) and may be attributable to (a) the neuroactive properties of steroid hormones and (b) the cyclic variation in serum levels.Estradiol inhibits y-aminobutyric acid (GABA) and potentiates glutamatergic transmission (5). It increases neuronal metabolism and discharge rates (5,6). It pro-

show abstract

“…15 In adult experimental animals, the thresholds of limbic seizures in female rats fluctuate during the estrus cycle inversely to serum estradiol levels. 16 Physiological doses of estradiol activate spike discharges 5,6,17,18 and lower the thresholds of seizures induced by electroshock, kindling, pentylenetetrazol, kainic acid, ethyl chloride, and other agents and procedures. [17][18][19][20][21][22] In rabbits, topical brain application, as well as intravenous systemic administration, of estradiol produces a significant increase in spontaneous electrically recorded paroxysmal spike discharges.…”

Section: Estradiolmentioning

confidence: 99%

“…16 Physiological doses of estradiol activate spike discharges 5,6,17,18 and lower the thresholds of seizures induced by electroshock, kindling, pentylenetetrazol, kainic acid, ethyl chloride, and other agents and procedures. [17][18][19][20][21][22] In rabbits, topical brain application, as well as intravenous systemic administration, of estradiol produces a significant increase in spontaneous electrically recorded paroxysmal spike discharges. 18 The increase is seen within a few seconds of application, which suggests a direct membrane rather than a genomic effect, and the increase is more dramatic in animals with pre-existent cortical lesions.…”

Section: Estradiolmentioning

confidence: 99%

Hormonal Therapies: Progesterone

Herzog¹

2009

Neurotherapeutics

View full text Add to dashboard Cite

Summary:Seizures do not occur randomly in the majority of people with epilepsy. They tend to cluster. Seizure clusters, in turn, commonly occur with a temporal rhythmicity that shows a readily identifiable and predictable periodicity. When the periodicity of seizure exacerbation in women conforms to that of the menstrual cycle, it is commonly known as catamenial epilepsy. This may be attributable to 1) the neuroactive properties of steroid hormones and 2) the cyclic variation in their serum levels. If hormones play a role in seizure occurrence, hormones may also have a role in treatment. Progesterone has potent GABAergic metabolites that may provide safe and effective seizure control in women who have catamenial epilepsy.

show abstract

Electrocortical Activation by Estrogens

Cited by 90 publications

References 7 publications

Seizure susceptibility in intact and ovariectomized female rats treated with the convulsant pilocarpine

Seizure susceptibility in intact and ovariectomized female rats treated with the convulsant pilocarpine

Three Patterns of Catamenial Epilepsy

Hormonal Therapies: Progesterone

Contact Info

Product

Resources

About