Direct evidence of active sympathetic vasodilatation in the skin of the human foot.

Abstract

SUMMARY1. During operative aorto-femoral vascular reconstructions on sixteen patients, the sympathetic chain was stimulated electrically between the L2 and L4 ganglia while blood flow was monitored by laser doppler flowmeters from the skin on the sole of the foot and the ankle and by an electromagnetic flowmeter from the deep femoral artery. Epidural anaesthesia to at least the T6 level was used which excluded reflex effects.2. Stimulation (10 Hz) at 1-12 mA current strengths for 30 s evoked both reductions and increases of blood flow in glabrous and hairy skin. Initial short-lasting flow increases (durations 9-19 s) followed by sustained decreases were common; sometimes there were sustained flow increases at low and decreases at high current strengths.3. In the deep femoral artery (supplying predominantly muscle) only flow reductions were evoked.4. The results provide evidence for sympathetically mediated vasodilatation in the skin of the human foot whereas leg muscles may be supplied by vasoconstrictor nerves only.

Effects of Adrenoceptor Antagonists on the Cutaneous Blood Flow Increase Response to Sympathetic Nerve Stimulation in Rats with Persistent Inflammation.

“…Changed vascular response to sympathetic nerve stimulation was not limited to inflamed condition: Lundberg et al reported that the electrical stimulation of the sympathetic nerve caused cutaneous vasodilatation in patients with obstructive vascular disease [29]. We also measured BF in rats with chronic constriction injury using the same methods as in the present experiment, and found a BF-increase response to SS similar to that in AI rats (data not shown).…”

Effect of baseline vascular tone on vasomotor responses in cat lip.

“…The phenomenon reported by Allwood et al (1959) and Elam & Wallin (1987), that subjects with a low baseline blood flow tend to vasodilate, whereas those with a high baseline flow tend to vasoconstrict, in response to mental stress, is analogous to our finding that simultaneous stimulation of vasoconstrictor and vasodilator fibres induces vasodilatation at a low BRCF, but vasoconstriction at a high BRCF (Fig. 4), with the proviso that sympathetic rather than parasympathetic vasodilator fibres supply the skin of the limbs (Lundberg et al 1989). Oberle et al (1988) also reported that cold subjects, in whom the skin temperature was less than 25°C, responded to intraneural electrical stimulation of the median nerve, to mental stress or arousing stimuli, and to deep breaths with cutaneous vasodilatation, whereas the same stimuli given to warm subjects, with a skin temperature of more than 30°C, usually evoked cutaneous vasoconstriction.…”

Spinal Cord Stimulation in Severe, Inoperable Peripheral Vascular Disease

“…Another clinical study, which helps validate this proposed mechanism, was offered by Lundberg et al( 22). During aorto‐femoral reconstruction, 16 patients were electrically stimulated along their sympathetic chain from L2‐L4 ganglia.…”