Unit:
Τομέας Βασικών ΕπιστημώνLibrary of the School of Health Sciences
Dissertation committee:
Λιάπη Χάρις, Αναπληρώτρια Καθηγήτρια, Τμήμα Ιατρικής, ΕΚΠΑ
Τεσσερομάτη Χριστίνα, Ομότιμη Καθηγήτρια, Τμήμα Ιατρικής, ΕΚΠΑ
Τσαρμπόπουλος Αντώνιος, Αναπληρωτής Καθηγητής, Τμήμα Ιατρικής, ΕΚΠΑ
Κάσση Ευανθία, Επίκουρη Καθηγήτρια, Τμήμα Ιατρικής, ΕΚΠΑ
Αντωνίου Αικατερίνη,Αναπληρώτρια Καθηγήτρια, Τμήμα Ιατρικής, Πανεπιστήμιο Ιωαννίνων
Δάλλα Χριστίνα, Αναπληρώτρια Καθηγήτρια, Τμήμα Ιατρικής, ΕΚΠΑ, Επιβλέπουσα
Τραφάλης Δημήτριος, Επίκουρος Καθηγητής, Τμήμα Ιατρικής, ΕΚΠΑ
Original Title:
Διακυμάνσεις συμπεριφερικών βιοχημικών και ενδοκρινικών δεικτών ντοπαμινεργικής δραστηριότητας κατά τις διάφορες φάσεις του οιστρογονικού κύκλου του επίμυος
Translated title:
Behavioral, biochemical, endocrine fluctuations of the dopaminergic activity, during the estrous cycle of the rat
Summary:
The effect of estrogen on dopaminergie activity remains a matter of controversy. Basic and clinical research has indicated that estrogen axerts a modulatory influence on dopaminergic-related processes.
The purpose of this study was to determine whether variations in serum estradiol over the estrous cycle would affect DA-related functions.
Experimentally naïve female Wistar rats, weighing 150±10gr were used. Vaginal smears were taken daily between 11 and 12 a.m. and examined and only rats exhibiting three consecutive 4 day estrous cycles were selected, i.e. (Proestrous, Estrous, Metestrous, Diestrous).
Groups of animals were administered apomorphine (subcutaneously). 25μg/kg, 250μg/kg – placed in the open field and locomotion, rearings and groomings were recorded. Additionally, groups were administred750μg/kg APO and tested for stereotypy and another group of animals was tested for hypothermia after injection of apomorphine 400μg/kg. Another group of animals were injected intraperitoneally with haloperidol (1 and 2mg/kg) and tested for catalepsy.
At the completion of each test, animals were decapitated by guillotine, blood was collected from the severed neck vessels and analyzed for estradiol. The brain was removed and prefrontal cortex, nudeus accumbens and striatum weredissected and analyzed for DOPAC, DA and HVA.
The results of this study were the following.
Open field behaviors were not dependent upon hormonal variations across the cycle.
On behavioral grounds we failed to indicate any correlation between functional output of presynaptic DA-ergic mechanisms and estrous cycle.
Behaviors mediated by postsynaptic DA receptions stimulation were differentially affected by the estrous cyclicity. Apomorphine – induced hyper locomotion and hypothermia was attenuated and increased respectively on PE, while stereotypy remained stable across the cycle. Ovariectomized rats exhibited more locomotion, rearings and grooming than intact females (mainly on PE).
Halopenidol – induced catalepsy was higher in female than in male rats, but it was not affected by estrous cyclicity.
Biochemical results showed:
Lower mesocortical and higher mesolimbic and migrostriatal DA turnover in intact female than in Ovariectomized and male rats.
Lower mesocortical DA turnover at E and higher nigrostriatal DA turnover at PE and E.
Apomorphine (dopamine agonist) and haloperidol (dopamine antagonist) disrupts the normal order of the phases of the cycle with respect to serum, estradiol level.
Our results show that the fluctuations of serum estradiol levels (and probably of other hormones) during the estrous cycle of the rat effect differentially the function of the various DA-ergic systems in the brain.
Main subject category:
Health Sciences
Keywords:
Dopamine, Estrogen, Apomorphine, Haloperodol
Number of references:
229
