In vitro progesterone effects on 3H-norepinephrine release from rat cerebral cortex slices
1Department of Cell and Molecular Biology, Faculty of Biological Sciences, P. Catholic University of Chile, Santiago.
Neuroreport
|September 3, 1993
Summary
Progesterone influences norepinephrine release in rat brain regions. This hormone modulates neurotransmitter release during the estrous cycle but not after ovariectomy or pregnancy, suggesting specific regulatory roles.
Area of Science:
- Neuroscience
- Endocrinology
Background:
- Progesterone is a key hormone influencing various physiological processes.
- Its role in modulating neurotransmitter release in the brain requires further elucidation.
Purpose of the Study:
- To investigate the in vitro effect of progesterone on norepinephrine release in rat brain slices.
- To examine these effects across different physiological states: estrous cycle, post-ovariectomy, and pregnancy.
Main Methods:
- Rat brain slices from the occipital region were used.
- Potassium-induced, calcium-dependent release of 3H-norepinephrine was measured.
- Effects were studied during the estrous cycle, after ovariectomy, and during pregnancy.
Main Results:
- Progesterone (0.05-5 microM) reduced K+-induced norepinephrine release during all stages of the estrous cycle.
- Progesterone did not alter norepinephrine release in slices from ovariectomized or pregnant rats, or in male rat slices.
- Yohimbine, an alpha-2 antagonist, blocked the effect of progesterone.
Conclusions:
- Progesterone modulates norepinephrine release in the cerebral cortex.
- These findings suggest that the norepinephrine releasing process is a target for progesterone's influence on brain function.
- The modulatory effect appears specific to certain physiological conditions, particularly the estrous cycle.
