Inhibitory effects of prostaglandin E1 on responses of rabbit ear artery to nerve stimulation and on release of norepinephrine.

PGE1 in concentrations of 7 x 10(-9) to 4.5 x 10(-7) M inhibited the vasoconstrictor responses of the perfused rabbit ear artery to nerve stimulation. The degree of inhibition was dependent on the concentration of PGE1, as well as on the train length and frequency of stimulation. The vasoconstriction produced by norepinephrine was not altered by 1.1 x 10(-7) M PGE1. This substance markedly reduced the stimulation-evoked outflow of 3H-norepinephrine from the artery. The findings indicate that PGE1 inhibits the vasoconstrictor responses of rabbit ear artery to sympathetic nerve stimulation by reducing the release of the sympathetic transmitter for adrenergic nerve endings.