Effects of atrial natriuretic factor on noradrenergic neurotransmission in vivo in the rat mesentery.

The effects of synthetic atrial natriuretic factor (ANF) on noradrenergic neurotransmission were assessed in the in situ blood-perfused rat mesentery. Synthetic ANF was infused (.003-1 micrograms/min) directly into the mesenteric artery, and vascular responses to periarterial (i.e., sympathetic) nerve stimulation (PNS) and exogenous norepinephrine (NE) were elicited. Synthetic ANF did not significantly alter vascular responses to PNS and only slightly suppressed responses to exogenous NE at blood levels greater than 10 ng/ml. In contrast, under similar conditions, low doses of adenosine attenuated vascular responses to PNS without reducing responses to exogenous NE, and high doses of adenosine nearly abolished responses to both PNS and exogenous NE. We conclude that synthetic ANF exerts very little influence on noradrenergic neurotransmission in the rat mesenteric vascular bed.