Estrogen Nurtures the Upper Chambers of the Heart

Atrial naturiuretic peptide is a cardiac hormone produced predominantly in the atria of the heart. Atrial natriuretic peptide induces relaxation of coronary arteries, inhibition of L-type Calcium channels* in the myocardium, suppression of the renin angiotensin system and decreased sympathetic nervous system activity. These effects are protective to the cardiovascular system and are also induced by estrogen.

The atria are the two upper chambers of the heart. Estrogen receptors are expressed in the atria. There is an increased expression and secretion of atrial natriuretic peptide in response to estrogen receptor activation.

However, during the menopausal transition and for women of postmenopausal years, diminished estrogen production can offset any of the protective regulatory mechanisms provided by artrial natriuretic peptide. For menopausal and postmenopausal women such symptoms can include heart palipitations due to altered intercellular calcium handling and hypertension due to angiotensin activity and a shift in sympathovagal balance.

*L-type calcium channels are located on vascular smooth muscle, cardiac myocytes and cardiac nodal tissue (sinoatrial and atrioventricular nodes). These channels are responsible for regulating the influx of calcium into muscle cells, which in turn stimulates smooth muscle contraction (blood pressure) and cardiac myocyte contraction (heart beat).

Source:
Estrogen Receptors Activate Atrial Natriuretic Peptide in the Rat Heart
Marek Jankowski, Grazyna Rachelska
PNAS Sept 2001, Vol. 98, no 20, 11765-11770