Alteration of muscarinic binding in specific brain areas following estrogen treatment.

Systemic administration of estradiol benzoate (EB) to ovariectomized female rats significantly altered cholinergic muscarinic binding of [3H]quinuclidinyl benzilate in discrete brain regions. Specifically, EB increased muscarinic binding in the medial basal hypothalamus (MBH) and decreased muscarinic binding in the medial preoptic area (POA). These alterations were dose-dependent and appeared to reflect changes in the number of muscarinic binding sites. Treatment with EB failed to significantly affect binding in several control areas in females or in the MBH and POA of males.