Binding of tritiated yohimbine to platelets in women with maternity blues

Adrenergic receptors in premenstrual dysphoric disorder: I. Platelet alpha 2 receptors: Gi protein coupling, phase of menstrual cycle, and prediction of luteal phase symptom severity

BACKGROUND

Abnormal alpha 2-adrenergic receptor (AR) function is implicated in anxiety and depressive disorders. Premenstrual dysphoric disorder (PMDD) is characterized by anxiety and depressive symptoms, which may be associated with changes in alpha 2AR function. Previous studies on alpha 2AR function during phases of the menstrual cycle in controls and PMDD patients are inconsistent.

METHODS

alpha 2AR function was examined in 16 PMDD patients and 15 controls during the follicular phase, and in 10 PMDD patients during late luteal phase. Antagonist-measured maximum binding capacity, agonist-measured receptor density in high- and low-conformational states, and agonist affinity to both states were measured. Coupling efficiency to Gi protein was estimated.

RESULTS

There were no significant differences in coupling efficiency. PMDD patients had significantly low antagonist affinity; there were no differences in other binding parameters. There were no changes in alpha 2AR binding parameters between phases of menstrual cycle in PMDD women. alpha 2AR density and symptom severity were inversely related during the follicular phase in controls and patients. During luteal phase, alpha 2AR density correlated positively with symptom severity in patients. High follicular alpha 2AR density predicted more severe luteal symptoms in PMDD patients.

CONCLUSIONS

These findings are discussed in view of the molecular biology of alpha 2AR, and their role in PMDD, anxiety, and depressive disorders.

Postpartum blues: relationship between not-protein bound steroid hormones in plasma and postpartum mood changes

The relationship between non-bound steroid hormone levels in plasma and the occurrence of postpartum mood changes was investigated in 26 newly delivered mothers throughout the first 5 days postpartum. Studies with saliva samples had reported higher concentrations of 17 beta-estradiol and progesterone on the days of symptoms in women experiencing postpartum blues. As there had been a controversy as to how far saliva concentrations reflect free hormone levels in plasma, free hormone levels of 17 beta-estradiol and progesterone were determined in plasma using ultrafiltration. No significant difference concerning free hormone levels could be found between women with and without postpartum blues.

Do biochemical factors play a part in postnatal depression?

1. There are major changes in progesterone, oestrogen, cortisol and beta-endorphin level associated with parturition, and as all these can be psychoactive it is likely that they contribute to the mood changes that can occur at this time. However evidence for their involvement is, at present, indirect. 2. Postnatal depression itself appears to be a heterogeneous condition with different times of onset, and it is probable that various biological and social factors play a role to a differing degree in different individuals. 3. About half of postnatal depression appears to arise in the first two weeks after childbirth. Some cases follow a period of early euphoria. 4. A different subgroup is associated with thyroid dysfunction, which peaks two to five months postpartum. 5. The tyramine test does not predict vulnerability to postnatal depression. 6. It is suggested that in future research the time course of onset of the depression, and the nature of the mood changes that occur in the first postpartum week, are investigated as possibly relevant variables.

Effect of estradiol implant on noradrenergic function and mood in menopausal subjects

The effect of the alpha 2-adrenoceptor agonist, clonidine, on plasma growth hormone (GH), plasma 3-methoxy-4-hydroxyphenylethylenegylcol (MHPG), blood pressure and sedation were studied in 16 menopausal subjects before and 6 wk after a 100-mg implant of estradiol. The specific binding of tritiated yohimbine to intact platelets also was studied. Estradiol implants increased basal GH output and reduced baseline MHPG and sedation scores. However, none of the subsequent responses to clonidine were altered. Platelet yohimbine binding also was unchanged following the implant. Both observer- and self-rating scales showed a marked reduction in anxiety and depression scores. The results suggest that estradiol may alter some indices of noradrenergic function, but that the mechanism does not involve alterations in alpha 2-adrenoceptor sensitivity.

Types and characteristics of short-term course of depression after delivery: using Zung's Self-Rating Depression Scale

In order to clarify the prevalence and clinical features of so-called "maternity blues" and the relationship with depression after delivery, we conducted a prospective study on 220 mothers using the Zung's Self-Rating Depression Scale (ZSDS) 4-7 days after childbirth and again one month after childbirth. Their physical condition during their pregnancy had been evaluated earlier. As in a previous epidemiological study conducted in Japan, we classified subjects with a ZSDS score of 60 and over as a high scoring group. Eighteen mothers (8.18%) fell into this group ("maternity blues" group) in the one week post-partum evaluation. Comparing the ZSDS scores one month after childbirth with the earlier scores, in 10 women (4.5%), their scores decreased from 60 and over to below 60 (a "maternity blues" core group), and in 8 women (3.6%), their scores were still over 60 (a prolonged "maternity blues" group). Eleven (5.0%) out of the 202 women whose scores at one week after childbirth were below 60 showed a high score (60 and over) one month after childbirth (a potential depression group). All in, 191 women scored below 60 in both evaluations. Although we could divide the subjects into 4 groups as described above, we could not find any clinical symptoms to distinguish between the 3 groups with "maternity blues" or depression in the evaluation one week after childbirth. However, one finding suggests that these three groups may have different features.

Endocrine aspects of postnatal mental disorders

Biological research in postnatal mental illness has only a short history and few encouraging data have yet emerged. The most promising positive findings are perhaps preliminary evidence for an increase of postnatal depression in women with postpartum thyroid dysfunction, some evidence for an enhanced sensitivity to changes in progesterone levels in postnatal depression, and the presence of an opioid peptide with unknown function in the cerebrospinal fluid of women with puerperal psychosis. Although steroid hormones are generally thought to be aetiologically relevant since they freely enter the brain and are known to interact with central monoamine neurotransmitter systems, attempts to demonstrate abnormal levels in postnatal disorders have been disappointing. An important reason for this outcome may be the usually employed approach of isolated hormone measurements. Ovarian steroid levels show marked interindividual variations. Thus significant between-group differences may only be obtained when large numbers of subjects are tested. Since only the unbound fraction can enter the brain, its measurement should be included in such studies. In the case of cortisol, single values are insufficient because of the pulsatile nature and the circadian pattern of its release. Thus serial sampling over 24 hours is more appropriate to detect secretory abnormalities. Measurements of circulating peptides are difficult to interpret since the amount reaching the brain is at best small. What is needed here are estimations of peptides in the cerebrospinal fluid which, however, pose ethical problems. Another explanation for the dearth of consistent positive data may be that women with postnatal mental disorders react to normal postnatal changes differently to women who remain well after childbirth. There is already evidence that patients at high risk of puerperal manic-depressive illness develop a hypersensitivity of central D2 receptors which may be related to the effects of oestrogen withdrawal on the function of DA systems. Further investigations of central neurotransmitter function are needed. In many ways postnatal mental disorders provide a unique opportunity for psychosomatic research since their onset can almost be predicted and follows an event which is associated with changes in many physiological systems. Results of recent neuropharmacological and behavioural investigations into the central effects of steroid and peptide hormones provide the basis for a multitude of pathogenetic hypotheses to be tested in postnatal mental disorders and research in this area may see exciting times ahead.