Fluoxetine Mimics the Anorectic Action of Estrogen and Its Regulation of Circadian Feeding in Ovariectomized Female Rats

The effect of fluoxetine on morning blood pressure surge in patients with ischemic stroke: a prospective preliminary clinical study

OBJECTIVE

Our study aimed to evaluate the effect of fluoxetine on morning blood pressure surge (MBPS) in patients with ischemic stroke.

METHODS

A total of 30 patients with acute ischemic stroke, 15 in the control group and 15 in the treatment group, were enrolled. Two patients in the control group and one in the treatment group were lost during follow-up. The patients in the treatment group were treated with fluoxetine (20 mg per day for 3 months) based on the treatments in the control group. Baseline characteristics, Patient Health Questionnaire 9 (PHQ-9) items scale score, mean blood pressure and MBPS were evaluated before and after treatment, and the correlation between the improvements of PHQ-9 scale score and MBPS was also analyzed.

RESULTS

The mean SBP and the systolic and diastolic MBPS in the treatment group were significantly lower than that in the control group after 3 months of treatment (P = 0.024, P = 0.022, P = 0.001, respectively). Besides, the improvement of PHQ-9 scale score was significantly higher in the treatment group than in the control group (P = 0.049). There was no significant correlation between the improvement of systolic or diastolic MBPS and the improvement of PHQ-9 scale score in the treatment group (P = 0.289 and P = 0.206, respectively).

CONCLUSION

Fluoxetine might improve MBPS in patients with ischemic stroke.

Estrogens and the circadian system

Circadian rhythms are ~24 h cycles of behavior and physiology that are generated by a network of molecular clocks located in nearly every tissue in the body. In mammals, the circadian system is organized hierarchically such that the suprachiasmatic nucleus (SCN) is the main circadian clock that receives light information from the eye and entrains to the light-dark cycle. The SCN then coordinates the timing of tissue clocks so internal rhythms are aligned with environmental cycles. Estrogens interact with the circadian system to regulate biological processes. At the molecular level, estrogens and circadian genes interact to regulate gene expression and cell biology. Estrogens also regulate circadian behavior across the estrous cycle. The timing of ovulation during the estrous cycle requires coincident estrogen and SCN signals. Studies using circadian gene reporter mice have also elucidated estrogen regulation of peripheral tissue clocks and metabolic rhythms. This review synthesizes current understanding of the interplay between estrogens and the circadian system, with a focus on female rodents, in regulating molecular, physiological, and behavioral processes.

Influence of exogenous and endogenous estrogen on thermoregulatory responses to mild heat and the interaction with light and dark phases

The present study aimed to determine the influence of estradiol (E2) and the interaction with circadian phases on thermoregulatory responses to mild heat in female rats. Heat loss and production during 3-h exposure to the environment at an ambient temperature of 28-34 °C were assessed by measuring abdominal temperature (Tabd), tail skin temperature, and oxygen consumption in ovariectomized rats with and without E2 replacement (OVX + E2 and OVX, respectively) and in control rats in the proestrus (P) and diestrus (D) phases. In the light phase, Tabd remained unchanged in all groups. Tabd increased in the dark phase, but was lower in the OVX + E2 and P groups than in the OVX and D groups. Oxygen consumption decreased at 34 °C, but to a lesser extent in the OVX + E2 group than in the OVX group. These results suggest that E2 activates thermoregulation in mild heat in the dark phase.