Effect of histamine and prostaglandin E2 on the microcirculation in the skin.

The response of the cutaneous microvasculature to two vasoactive mediators, histamine and prostaglandin E2, was measured by laser Doppler velocimetry. Four concentrations of histamine (1.01 to 65.1 X 10(-5) M, in fourfold dilutions) were injected intradermally into the forearms of six healthy subjects: Prostaglandin E2 (1.77 to 114.0 X 10(-8) M, also in fourfold dilutions) was injected several weeks later. The blood flow at the injection site was measured by laser Doppler velocimetry at five minute intervals until the response resolved. Both mediators produced hyperaemia with markedly accelerated cutaneous blood flow. Analysis of the dose response data showed that, for a given mediator, the differences in responses between subjects were not substantial and, in particular, that the kinetics of the decay of hyperaemia did not vary significantly between subjects. The response to histamine differed from that to Prostaglandin E2 in terms of time to maximum response, duration of maximum response and coefficient of decay.