Postmenopausal hypoestrogenism increases vasoconstrictor neuropeptides and decreases vasodilator neuropeptides content in arterial-wall autonomic terminations.

OBJECTIVE: To investigate the effects of postmenopausal hypoestrogenism on the content of autonomic vasoconstrictor (neuropeptide Y) and vasodilator neuropeptides (vasoactive intestinal peptide and substance P) at the arterial level.
DESIGN: Prospective, clinical study.
SETTING: Department of Gynecology and Obstetrics and Pathophysiology of Human Reproduction, University of Naples "Federico II," Naples, Italy. PATIENT(S): Twenty premenopausal women and 20 postmenopausal women, matched for age and parity. INTERVENTION(S): All patients underwent abdominal hysterectomy with bilateral oophorectomy for benign conditions. During surgery, a sample of uterine artery was obtained. The presence of E2, estrogen receptor alpha (ER alpha), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), and S100 (a generic neuronal marker) was evaluated by means of immunohistochemistry and Western-blot analysis. MAIN OUTCOME MEASURE(S): Mean arterial content of E2, ER alpha, VIP, NPY, and SP. RESULT(S): Both immunohistochemical and Western-blot analysis showed that after menopause, the reduction in E2 and ER alpha in the uterine artery wall is associated with a decrease in vasodilator neuropeptides and an increase in vasoconstrictor NPY. A similar immunopositivity for S100 was observed in pre- and postmenopausal samples, which demonstrated similar total neuronal fiber contents. CONCLUSION(S): Postmenopausal hypoestrogenism seems to increase arterial vascular tone through a reduction of vasodilator neuropeptides and an increase in vasoconstrictor peptides in the arterial-wall termination of the autonomous system. These changes in neuropeptide content in the arterial walls might represent a new mechanism underlying the negative effects of menopause on the cardiovascular system.