Biomedical subjects

Anna-Carin Wihlbäck

Publications and source records attributed to Anna-Carin Wihlbäck.

4 recordsLinked to original sources

PubMed2005

Neuroactive steroid effects on cognitive functions with a focus on the serotonin and GABA systems.

This article will review neuroactive steroid effects on serotonin and GABA systems, along with the subsequent effects on cognitive functions. Neurosteroids (such as estrogen, progesterone, and allopregnanolone) are synthesized in the central and peripheral nervous system, in addition to other tissues. They are involved in the regulation of mood and memory, in premenstrual syndrome, and mood changes related to hormone replacement therapy, as well as postnatal and major depression, anxiety disorders, and Alzheimer's disease. Estrogen and progesterone have their respective hormone receptors, whereas allopregnanolone acts via the GABA(A) receptor. The action of estrogen and progesterone can be direct genomic, indirect genomic, or non-genomic, also influencing several neurotransmitter systems, such as the serotonin and GABA systems. Estrogen alone, or in combination with antidepressant drugs affecting the serotonin system, has been related to improved mood and well being. In contrast, progesterone can have negative effects on mood and memory. Estrogen alone, or in combination with progesterone, affects the brain serotonin system differently in different parts of the brain, which can at least partly explain the opposite effects on mood of those hormones. Many of the progesterone effects in the brain are mediated by its metabolite allopregnanolone. Allopregnanolone, by changing GABA(A) receptor expression or sensitivity, is involved in premenstrual mood changes; and it also induces cognitive deficits, such as spatial-learning impairment. We have shown that the 3beta-hydroxypregnane steroid UC1011 can inhibit allopregnanolone-induced learning impairment and chloride uptake potentiation in vitro and in vivo. It would be important to find a substance that antagonizes allopregnanolone-induced adverse effects.

Animals↗

PubMed2005

Estradiol and the addition of progesterone increase the sensitivity to a neurosteroid in postmenopausal women.

The aim of this study was to compare the pharmacodynamic response to a neuroactive steroid, pregnanolone, before and during different hormonal settings of postmenopausal hormone replacement therapy (HRT), using natural progesterone. A second aim was to investigate whether the response to pregnanolone was associated with cyclicity in negative mood symptoms during treatment. Twenty six postmenopausal women with climacteric symptoms were administered HRT in a randomized, double blinded, placebo-controlled, crossover study. The women received 2 mg oral estradiol (E(2)) continuously during two 28-day cycles and 800 mg of vaginal progesterone or placebo sequentially for the last 14 days of each treatment cycle. Pharmacodynamic response to pregnanolone was assessed before treatment, and during the last week of each treatment cycle, by comparing the effects of intravenous pregnanolone (3alpha-hydroxy-5beta-pregnan-20-one) on saccadic eye velocity (SEV), saccade acceleration, saccade latency and self-rated sedation. Throughout the study daily symptom rating scales were kept. According to the daily symptom rating scales, patients were divided into two groups; one group who displayed a significant variance in negative mood symptoms during HRT (cyclicity) and one group with no cyclical changes in negative mood symptoms during treatment. During treatment with either E(2) alone or E(2)+progesterone the response in saccadic eye movement parameters and in self-rated sedation to pregnanolone was enhanced compared to pretreatment values. The SEV, saccade acceleration and sedation responses to pregnanolone was also increased in women expressing cyclicity in negative mood symptoms compared to women with no cyclical changes in negative mood during HRT. In conclusion, during treatment with either E(2) alone, or E(2)+progesterone, pregnanolone sensitivity was increased. Women expressing cyclicity in negative mood symptoms were more sensitive to pregnanolone than women without symptom cyclicity during HRT.

Adult↗

PubMed2004

Influence of menstrual cycle on platelet serotonin uptake site and serotonin2A receptor binding.

Depression and anxiety are common health problems affecting women, particularly during the reproductive years. Major depression is two to three times as common in women than in men. Neuroendocrine factors are likely to contribute to this overall increased risk for developing mood disorders in women, and the neuroendocrine influence is most obviously seen in women with premenstrual dysphoric disorder (PMDD) as these women experience depressed mood and anxiety premenstrually only during ovulatory cycles. Moreover, dysfunction of serotonergic transmission has been regarded as an important mechanism in several psychiatric disorders and ovarian steroids have been shown to profoundly influence the activity of the serotonergic system. Given these facts, the purpose of this study was to examine whether binding of [3H]paroxetine to the platelet serotonin transporter or binding of [3H]lysergic acid diethylamide ([3H]LSD) to the platelet 5-HT2A receptor are influenced by the cyclical changes in circulating estradiol and progesterone that occur during the menstrual cycle. We examined 28 healthy women, without oral contraceptives and with regular menstrual cycles. In the late follicular phase, Bmax for [3H]paroxetine binding was significantly higher than in the ovulatory (p<0.01), early luteal phase (p<0.05) and mid-luteal phase (p<0.01). Bmax for [3H]LSD binding was significantly higher in the early follicular phase and the early luteal phase compared to the mid-luteal phase (p<0.001 and p<0.05, respectively). In the early follicular phase and the ovulatory phase, significant correlations between estradiol serum concentrations and Kd for [3H]paroxetine were obtained (p<0.001, respectively). In the luteal phase, significant inverse correlations between progesterone as well as estradiol serum concentrations and Kd for [3H]LSD binding were found (p<0.05, respectively).

Adult↗

PubMed2003

Pathogenesis in menstrual cycle-linked CNS disorders.

That 3alpha-hydroxy-5alpha/beta-pregnane steroids (GABA steroids) have modulatory effects on the GABA-A receptor is well known. In behavioral studies in animals high exogenous dosages give concentrations not usually reached in the brain under physiological conditions. Animal and human studies show that GABA-A receptor-positive modulators like barbiturates, benzodiazepines, alcohol, and allopregnanolone have a bimodal effect. In pharmacological concentrations they are CNS depressants, anesthetic, antiepileptic, and anxiolytic. In low dosages and concentrations, reached endogenously, they can induce adverse emotional reactions in up to 20% of individuals. GABA steroids can also induce tolerance to themselves and similar substances, and rebound occurs at withdrawal. Menstrual cycle-linked disorders can be understood by the concept that they are caused by the action of endogenously produced GABA-steroids through three mechanisms: (a) direct action, (b) tolerance induction, and (c) withdrawal effect. Examples of symptoms and disorders caused by the direct action of GABA steroids are sedation, memory and learning disturbance, clumsiness, increased appetite, worsening of petit mal epilepsy, negative mood as tension, irritability and depression during hormone treatments, and the premenstrual dysphoric disorder (PMDD). A continuous exposure to GABA steroids causes tolerance, and women with PMDD are less sensitive to GABA-A modulators. A malfunctioning GABA-A receptor system is related to stress sensitivity, concentration difficulties, loss of impulse control, irritability, anxiety, and depression. An example of withdrawal effect is "catamenial epilepsy," when seizures increase during menstruation after the withdrawal of GABA steroids. Similar phenomena occur at stress since the adrenals produce GABA steroids during stress.

Affect↗