Calea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects, and increases the hippocampal activity during REM sleep in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Calea zacatechichi is a plant with an extensive popular and ritual use in Mexico. In healthy volunteers, it induces well-being and tranquility senses, and facilitates superficial stages of sleep. However, anxiolytic, and antidepressant-like effects and changes on the sleep-waking stages have not been explored.

AIM

To determine anxiolytic and antidepressant-like effects of an aqueous extract of C. zacatechichi (CZ) in rodents and to analyze their effects on hippocampal activity in the rat sleep-waking cycle.

MATERIAL AND METHODS

CZ anxiolytic- and antidepressant-like effects were evaluated in several mice and rat behavioral paradigms. CZ effects on temporal distribution of sleep were described, and hippocampus EEG frequency patterns were analyzed during the sleep-waking cycle; absolute and relative powers were analyzed during Rapid Eye Movements (REM) and non-REM sleep stages. CZ chemical analysis was performed by UPLC-ESI-MS.

RESULTS

CZ produced specific and robust anxiolytic- and antidepressant-like effects in mice and rats, similar to those of prototypical drugs, at doses ranging from 0.5 to 50 mg/kg. CZ at 100 mg/kg produced visible mild sedative effects in rats, associated with a significant increase in Slow Wave Sleep episodes during a 6 h recording, and enhanced fast frequencies of hippocampus (gamma-band:31-50 Hz) during REM sleep.

CONCLUSION

Results could support the well-being and tranquility senses reported by healthy consumers, and to explain the oneiric content during dreams and some improvements in cognitive processes described by consumers. Anxiolytic- and antidepressant-like effects of this species, reported for first time in this study could improve some aspects of mental health.

Ovariectomy differential influence on some hemostatic markers of mice and rats

Rodent ovariectomy is an experimental method to eliminate the main source of sexual steroids. This work explored for the first time the ovariectomy temporal changes induced in the hemostatic coagulation markers: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB) along with uterine weight on adult female CD1 mice and Wistar rats. Uterine weight (Uw) was assessed before ovariectomy (control), and 1, 3, 5, 7, 9, 16, and 21 days after surgery. PT, aPTT, TT and FIB were estimated the same days, using reported standard techniques. Ovariectomy decreased Uw, since day 1; and from day 10 to 21 reached the lowest values for both species. After day 1, mice hemostatic parameters changed (PT +10%, P<0.05; aPTT +53%, P<0.05; TT −24%, P<0.05; FIB +67%, P<0.05). Rats showed significant changes only in TT and FIB (TT −13%, P<0.001; FIB +65%, P<0.001). Neither mice PT, aPTT and TT, recovered control values after 21 days. In the rats from day 5 to 16 aPTT diminished (18–23%, P<0.05) recovering to control values on day 21, TT after 9 days and PT on day 16. In both species, FIB returned to its control values after 9 days. Ovariectomy differentially altered the PT hemostatic parameter of mice and rats indicating a non-equivalence among both species behaviour for experimental studies of blood coagulation.