Cigarette smoking, prostaglandins and reactive hyperemia.

The hypothesis was investigated that cigarette smoking obstructs the blood flow response that develops as a protection against tissue damage in an organ subjected to ischemia (reactive hyperemia). Forearm blood flow was recorded at rest and following forearm ischemia before and after cigarette smoking in healthy male and female volunteers. The experiments were also repeated after pre-treatment of the subjects with indomethacin, a prostaglandin synthesis inhibitor. Before pre-treatment with indomethacin, ischemia induced a reactive hyperemia amounting to 20 +/- 4 ml/100 ml tissue. This hyperemia was significantly (p less than 0.01) reduced by cigarette smoking, to 12 +/- 3 ml/100 ml tissue. After indomethacin, which in itself lowered the reactive hyperemia to 8 +/- 2 ml/100 ml tissue, smoking did not elicit any effect. It is suggested that smoking counteracts reactive hyperemia in tissues by interfering with the same physiological mechanism as indomethacin, i.e. with the vascular formation of PG. The possible significance of this observation in relation to cigarette smoking and ischemic heart disease is stressed.