The effects of prostaglandins E1, E2 and F2alpha on the cutaneous vasculature of the rat.

1 The responses of the rat cutaneous vasculature to prostaglandins E1, E2 and F2alpha have been investigated by a photomicrographic technique. 2 Prostaglandin E1 produced transient arterial constriction which was blocked by local pretreatment of preparations with compound 48/80 or methysergide. It was concluded that prostaglandin E1 produced vasoconstriction by release of 5-hydroxytryptamine (5-HT) from mast cells. The magnitude of the vasoconstrictor response appeared to be subject to seasonal variation. 3 Prostaglandin F2alpha produced arterial constriction of longer duration which was not blocked by compound 48/80, methysergide or phenoxybenzamine. 4 Preparations pretreated with prostaglandin F2alpha were found to be more sensitive to the venous constrictor effect, and less sensitive to the arterial constrictor effect, of noradrenaline. 5 Prostaglandin E2 produced arterial constriction which was usually partially blocked by compound 48/80 and methysergide and it was concluded that a major component of the vasoconstrictor response to prostaglandin E2 was of the E1 type but some component was of the F2alpha type.