The beginning of a fantastic, unanswered question: is 5-HT involved in systemic hypertension?

摘要

serotonin (5-hydroxytryptamine, 5-HT) was one of the first vasoactive amines to be discovered. As 5-HT is concentrated in the blood platelet to near millimolar concentrations, one might suspect that 5-HT would have significant impact as to how blood vessels, which carry the platelet, would function. In 1970, Don D. McGregor and Sir Horace Smirk (Figs. 1 and 2; kindly provided by Dr. JanetLedingham, New Zealand) of the Otago University Medical School published a paper in the American Journal of Physiology (5) that began a line of research in hypertension investigating questions that are still being argued.Their paper was entitled "Vascular response to 5-hydroxytryptamine in genetic and renal hypertensive rats" (5). The purpose of this study was to determine whether the mechanical advantage that an artery possessed in hypertension (thicker, stiffer wall compared with normal vessel) could completely explain the hyperreactivity to agonists, such that responses to agonists would be equivalently enhanced. Their experiments were straightforward and telling.They used two models of hypertension. The first was an inbred strain of New Zealand rats that develop hypertension genetically (GH), and the second was a renal model of hypertension in which a small silver clip was placed on the renal artery of the right kidney (2 kidney, 1 clip). Normal Wistar rats were used as controls. The effects of intravenous 5-HT on arterial blood pressure was examined in the chloralose-anesthetized state. Additionally, mesenteric arterial perfusion pressure in the isolated mesenteric arcade exposed to 5-HT, norepinephrine (NE), or angiotensin II (ANG II) was also measured.