The Circadian Rhythm of Blood Pressure During Pregnancy

To review the literature on the circadian rhythm of blood pressure during pregnancy. Data Sources : Computerized searches on MEDLINE, CINAHL, and MIRLYN. Study Selection : Selected studies from 1969 to 1997 were evaluated. Data Extraction : Data were extracted and information was organized under the following areas: definition of and the interconnection between circadian rhythm and blood pressure; the circadian variability of blood pressure throughout the trimesters; the patterns of the circadian rhythm of blood pressure in pregnancies defined as normal and those complicated by chronic hypertension and preeclampsia; and clinical implications. Data Synthesis : The circadian rhythm of blood pressure in pregnancy is the same as in the nonpregnant state, with a nocturnal decrease, especially during sleep. In patients with chronic hypertension, the nocturnal fall in blood pressure may be steeper. Patients with mild preeclampsia may experience a less pronounced nocturnal decrease in blood pressure. Patients with severe preeclampsia may display a reversed circadian rhythm, with no decrease and/or an increase in nocturnal blood pressure. Conclusions : The patterns of the circadian rhythm of blood pressure during normal pregnancy and pregnancies complicated by chronic hypertension and preeclampsia warrant consideration when monitoring patients and implementing management plans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71412/1/j.1552-6909.2000.tb02771.x.pd

Melatonin Membrane Receptors in Peripheral Tissues: Distribution and Functions

Many of melatonin’s actions are mediated through interaction with the G-protein coupled membrane bound melatonin receptors type 1 and type 2 (MT1 and MT2, respectively) or, indirectly with nuclear orphan receptors from the RORα/RZR family. Melatonin also binds to the quinone reductase II enzyme, previously defined the MT3 receptor. Melatonin receptors are widely distributed in the body; herein we summarize their expression and actions in non-neural tissues. Several controversies still exist regarding, for example, whether melatonin binds the RORα/RZR family. Studies of the peripheral distribution of melatonin receptors are important since they are attractive targets for immunomodulation, regulation of endocrine, reproductive and cardiovascular functions, modulation of skin pigmentation, hair growth, cancerogenesis, and aging. Melatonin receptor agonists and antagonists have an exciting future since they could define multiple mechanisms by which melatonin modulates the complexity of such a wide variety of physiological and pathological processes

Smoking effects on prolactin levels at pregnancy and lactation

The effect of smoking on prolactin levels was studied on women of different nutritional status, at the end of pregnancy and in the first month of lactation Smoking (S, n=74) and non-smoking pregnant (NS, n=67) women were followed from the 35-38 weeks of pregnancy to the first month post-partum (S=43, NS=32) Smokers had an average of 6 3 cigarettes Blood sampling and anthropometric measurements, were conducted, in the morning, after a period of relax of the subject. At lactation, two samples were collected BASAL and post-suckling (POST) after 20-30 minutes of breast-feeding At the end of pregnancy, prolactin levels increased according to nutritional status but smoking women had always lower prolactin levels for all nutritional status, except for undernourished women, where there was no difference At lactation, a significant difference was found for BASAL and POST samples in favour of non-smoking women (BASAL Non-smokers, 2316 (SD 1532) - Smokers 1726 (SD 1360) and POST: Non-Smokers 417