Sture Bevegård

Effect of prostaglandin E1 on forearm blood flow.

In nine healthy male volunteers, the effect on forearm blood flow of infusions of prostaglandin E1 (PGE1) in the brachial artery was studied by means of strain-gauge plethysmography. PGE1 invariably caused a rapid local increase in blood flow with doses of 10–5—10–4 μg · min-1 · kg-1. With 10–2 μg · min-1 · kg-1 of PGE1, the forearm blood flow increased to an average of 30 ml · min-1 · 100 ml-1 (range 15–43). The PGE1-induced vasodilatation was not blocked by atropine or propranolol, but could be abolished by simultaneous infusion of noradrenaline.

Adrenoceptors in Raynaud's disease.

Summary: Experiments were designed to study adrenoceptor function in subjects with Raynaud’s disease. Sympathetic agonists and antagonists were administered into the finger skin by iontophoresis, and the resulting change in local skin blood flow was evaluated by laser Doppler technique. The effects of norepinephrine (NE, stimulating α1-and α2-adrenoceptors), phenylephrine (stimulating α1-adrenoceptors), and B-HT 933 (stimulating α2-adrenoceptors) were studied in 12 women with Raynaud’s disease and in 12 healthy controls. Controls and cases showed a similar consistent vasoconstriction to NE and B-HT 933. All control subjects showed a vasoconstriction to phenylephrine. In contrast, the Raynaud subjects demonstrated a weaker vasoconstriction or even a vasodilation, especially to low concentrations of the drug. After blockade of the α1-adrenoceptors by doxazosin in the controls, phenylephrine mimicked the reaction in Raynaud subjects. β-Adrenoceptor agonists (isoprenaline and terbutaline) had no effect on finger blood flow in the examined finger skin area in either control or Raynaud subjects. We suggest that Raynaud’s disease is characterized by a defect in α1-adrenoceptor function.

Iontophoresis of vasoactive drugs Effect on peripheral blood flow during pregnancy

The aim of this study was to evaluate whether iontophoretic administration of the vasoactive agents noradrenalin (NA) and angiotensin (AII) combined with measurement of skin blood flow with a laser Doppler technique could serve as a predictive method for pre‐eclampsia.

EFFECT OF CHANGES IN BLOOD VOLUME DISTRIBUTION ON CIRCULATORY REGULATION AND CAROTID SINUS BAROREFLEX IN HEALTHY SUBJECTS AND PATIENTS WITH MODERATE HYPERTENSION

Publisher Summary In man, the intrathoracic low pressure receptors are stimulated rather selectively by changing the distribution of the blood volume. Carotid baroreceptors are stimulated also rather selectively by changing the pressure around the neck and with this technique both the dynamic and static components of the reflex is studied. The changes in receptor stimulation, induced in this way, are similar to those occurring physiologically. There is an evidence that the regulation of vascular resistance in skeletal muscles, that is in the forearm, is strongly influenced by receptors located on the low pressure side, whereas arterial baroreceptor seems to be of less importance. In earlier studies on healthy subjects, the gain of the carotid baroreceptors has been found to be inversely related to central venous pressure and, thus, likely to be modified by changes in signal level from intrathoracic low pressure receptors. The chapter discusses the possible role of low pressure baroreceptors in the pathogenesis of hypertension. Also it is of interest to study if the interaction between high pressure and low pressure baroreceptors is disturbed.