Estradiol application to one striatum produces postural deviation to systemic apomorphine

Area of Science:

• Neuroscience
• Endocrinology
• Behavioral Pharmacology

Background:

• Dopamine pathways are crucial for motor control and behavior.
• Estrogen is known to modulate neurotransmitter systems, including dopamine.
• The specific role of estrogen within the dorsal striatum in dopamine-mediated behaviors requires elucidation.

Purpose of the Study:

• To investigate whether estrogen directly acts within the dorsal striatum to influence dopamine-mediated behaviors.
• To determine if estradiol administration can alter apomorphine-induced stereotyped behaviors in rats.

Main Methods:

• Ovariectomized female Long-Evans rats received unilateral striatal applications of estradiol, cholesterol, or an empty cannula.
• Systemic injections of apomorphine (APO) were administered 1-4 hours post-insertion.
• Lateralization of stereotypic behaviors, specifically postural deviation, was measured.

Main Results:

• Unilateral dorsal striatal estradiol application induced lateralization of stereotypic behaviors ipsilateral to the insert.
• Estradiol was ineffective when inserted into the ventral striatum or neocortex.
• Neither cholesterol nor empty cannula controls produced behavioral lateralization.
• 17 alpha-estradiol and high doses of APO did not induce lateralization.

Conclusions:

• Estradiol acts directly within the dorsal striatum to antagonize apomorphine.
• This interaction results in the lateralization of apomorphine-induced stereotypic behaviors.
• Findings support a direct role for estrogen in modulating dopamine-mediated motor control in the dorsal striatum.