Prenatal and postnatal depression among low income Brazilian women

Postnatal depression is a significant problem affecting 10-15 percent of mothers in many countries and has been the subject of an increasing number of publications. Prenatal depression has been studied less. The aims of the present investigation were: 1) to obtain information on the prevalence of prenatal and postnatal depression in low income Brazilian women by using an instrument already employed in several countries, i.e., the Edinburgh Postnatal Depression Scale (EPDS); 2) to evaluate the risk factors involved in prenatal and postnatal depression in Brazil. The study groups included 33 pregnant women interviewed at home during the second and third trimesters of pregnancy, and once a month during the first six months after delivery. Questions on life events and the mother's relationship with the baby were posed during each visit. Depressed pregnant women received less support from their partners than non-depressed pregnant women (36.4 vs 72.2 percent, P<0.05; Fisher exact test). Black women predominated among pre- and postnatally depressed subjects. Postnatal depression was associated with lower parity (0.4 ñ 0.5 vs 1.1 ñ 1.0, P<0.05; Student t -test). Thus, the period of pregnancy may be susceptible to socio-environmental factors that induce depression, such as the lack of affective support from the partner. The prevalence rate of 12 percent observed for depression in the third month postpartum is comparable to that of studies from other countries

Effects of naltrexone and cross-tolerance to morphine in a learned helplessness paradigm

Opiates have been implicated in learned helplessness (LH), a phenomenon known to be related to opiate stress-induced analgesia (SIA). In the present study, we investigated the role of opiates in the induction of LH and SIA under different conditions. Adult female Wistar rats were trained either by receiving 60 inescapable 1-mA footshocks (IS group, N = 114) or by confinement in the shock box (control or NS group, N = 92). The pain threshold of some of the animals was immediately evaluated in a tail-flick test while the rest were used 24 h later in a shutttle box experiment to examine their escape performance. The opiate antagonist naltrexone (0 or 8 mg/kg, ip) and the previous induction of cross-tolerance to morphine by the chronic administration of morphine (0 or 10 mg/kg, sc, for 13 days) were used to identify opiate involvement. Analysis of variance revealed that only animals in the IS group demonstrated antinociception and an escape deficit, both of which were resistant to the procedures applied before the training session. However, the escape deficit could be reversed if the treatments were given before the test session. We conclude that, under our conditions, induction of the LH deficit in escape performance is not opiate-mediated although its expression is opiate-modulated.

Chronic but not acute Li+ treatment prevents behavioral depression in rats

The effect of lithium administration on the learned hellessness model of depression was investigated. Female Wistar rats (190-210g) received either tap water alone (N=156) or 20 mM LiCL, provided chronically (30 days; N = 127) or acutely (5 days; N = 22), in the drinking water. Three days before the end od treatment, each group was divided into two subgroups which received either inescapable shock (IS) or no shock (NS) treatment in shuttle boxes. All groups were subsequenty submitted to an escape test on the following day and then sacrificed one day after the escape test, when blood samples were taken to measure serum Li+, Na+ and K+ concentrations by flame photometry. There were no significant differences in serum Na+ amongst the 4 groups. chronically treated NS and IS rats both presented an increase in serum K+ compared to the control rats. The IS and not the NS chronically treated rats presented increased serum Li+ levels which cannot be accounted for in terms of differences in Li+ intake. The IS group treated chronically with lithium had a better escape performance than the IS group receiving either tap water or acute Li+ administration. We conclude that chronic but not acute Li+ treatment at a serum level within the prophylactic range (0,5 mEq) is able to prevent learned helplessness in the rat. These results agree with the data obtained in clinical practice indicating that li+ is only effective after chronic administration and that Li+ - induced hyperkalemia is a side effect

Lithium treatment prolongs shock-induced hypoalgesia

We have investigated the effect of chronic lithium (Li+) treatment on stress-induced hypoalgesia, a phenomenon known to be dependent on the activation and sensitization of the central opioid system. Adult female Wistar rats received either 20 mM LiCl in the drinking water (serum level of 0.5 mEq/l,N = 110) or tap water (controls N = 113) for 28 days. The rats were divided into three subgroups and were trained either by receiving 60 inescapable 1-mA footshocks (IS) while yoked to a escapable (ES) group, or by confinement (NS) to the shock box. As a control for the activation of the opioid system, we included rats injected with 0.9 percent saline (N = 24) or morphine (4 mg/kg, sc, N =20) before confinement. Twenty-four hours later, the rats (N = 187) were either submitted to five inescapable (1 s,0.6 mA) footshocks (shock reexposure) or received no shocks over the same period (N = 80). The pain threshold was estimated using a tail-flick apparatus after the training session and immediately after the shock reesposure. ANOVA followed by duncan's test indicated that hypoalgesia was produced soon after the training session in the morphine and shocked groups and persisted in the Li+-IS group for up to three days. Hypoalgesia was reinstated in the control IS and morphine groups by reexposure to the shochs, but was not modified in the Li+-IS groups. We conclude that Li+ treatment prolongs the hypoalgesia induced by inescapable shocks

Developmental toxicity of lithium treatment at prophylactic levels

Lithium (Li+) salts are frequently used in psychiatry and may be administered to women in theirreproductive years. We have investigated the influence of chronic Li+ administration on rat offspring. Pregnant Wistar rats drank either tap water ad libitum or 10 mM LiCl, or were water restricted (paired to rats receiving LiCl) until pup weaning. Following birth, pups were fostered to form five experimetnal groups (N = numbers of litters): a) Control-S, stressed by water restriction (N = 21), b) Li+ during the prenatal and lactating periods (N=18),c) Li+ during the prenatal period only (N=22), d) Li+ during the lactating period only (N = 15), and e) Control-NS no treatment (N = 13). Prenatal water restriction of Li+ treatment impaired the performance of the righting reflex, altered the number of males born and delayed the final date of eye opening. Postnatal water restriction or Li+ treatment of the dams reduced body growth and the date of eye opening of pups. No difference was found in the time to pup earflap opening, or in the motor coordination test. The specific effect of lithium on pups included impairment of the righting reflex, an increase in the number of males born, a reduction in body weight at weaning and a delay in the eye opening date. The serum Li+ levels of the dams were maintained at approximately 0.5 mEq/l. Ther was an increase in serum potassium, but not sodium, concentrations. We conclude that chronic treatment of dams with Li+ in amounts similar to those used in the prophylaxis of bipolar disorders aggravated the delay in physical and behavioral development of pups produced by stress associated with limited water intake and handling

Reversal of learned helplessness by chronic lithium treatment at a prophylactic level

1. The effect of chronic lithium (Li) administration in a learned helplessness (LH) model was investigated. Female Wistar rats (190-210 g) received either tap water ad libitum (N = 56) or 20 mM LiCl (N = 63) in the drinking water or were water restricted (35 per cent based on lower liquid intake of rats receiving lithium, N = 40) for 30 days. On the 28th day, each of these groups was divided into three subgroups which received escapable (ES), inescapable (IS) or no shock (NS) treatment in shuttle boxes. All groups were submitted to the escape test on the 29th day and sacrificed on the 30th day, when blood samples were taken for measurement of serum lithium, sodium and potassium concentrations. 2. The NS group had lower serum Li levels (0.36 +/- 0.06, N = 15) than the ES (0.46 +/- 0.07, N = 15) or IS group (0.44 +/- 0.09, N = 25). The Li-pretreated group subjected to IS had a more effective escape performance than the IS group under water restriction and showed the same behaviour as animals not submitted to shocks. 3. We conclude that chronic treatment with Li at a serum level of 0.44 +/- 0.09 mEq/l prevents learned helplessness in rats. These results corroborate the validity of the use of this model for the assessment of the capacity of Li to protect against some depressive episodes

Baclofen impairs passive and active avoidance performance in mice.

Prejuizo no desempenho de camundongos na esquiva passiva e ativa induzida por baclofen. Camundongos albinos, Webster foram injetados com baclofen, droga que atua interferindo com o sistema do acido gama-aminobutilico, e submetidos a treino de resposta de esquiva ativa de duas ou de esquiva passiva. Observou-se, para os grupos injetados com a droga, um desempenho prejudicado nos dois tipos de esquivas.Esses resultados nao podem ser atribuidos a fenomenos de dissociacao de aprendizagem, uma vez que o esquema de administracao da droga, utilizado no presente experimento, permite afastar essa hipotese. E discutido o possivel papel do acido gama-aminobutirico no fenomeno observado