THE ROLE OF VASOCONSTRICTOR 
AND VASODILATOR NERVES IN THE CONTROL 
OF THE PERIPHERAL CIRCULATION 
Ian C. Roddie 
Department of Physiology 
The Queen's University of Belfast 
Belfast, North Ireland 
Over the last few years, there has been a gradual development 
in our notions of the nervous control of peripheral blood vessels in 
man. Today I want to review the pattern which seems to be emerging. 
As you know, blood flow in the limbs is mainly distributed to skin 
and muscle and both these tissues appear to have a rich vasomotor 
innervation. All these fibres are not actively concerned in tempera- 
ture regulation but an understanding of their various functions is 
very helpful in the design and interpretation of experiments on the 
peripheral vascular responses to heat and cold. First of all, there- 
fore, I will deal with the vasomotor control of muscle vessels and 
then with that of skin vessels. 
VASOMOTOR NERVES TO MUSCLE 
Vasoconstrictor Fibres 
Until 1943 the available evidence si^gested that muscle blood 
vessels had little or novasoconstrictor innervation. When measured 
as soon as one week following cervical sympathectomy, forearm 
blood flow was not found to be increased (Stein, Harpuder, and Byer, 
1948). Blocking the deep nerves to the muscles did not increase the 
temperature of the overlying skin (Wool lard and Phillips, 1932; Grant 
and Pearson, 1938). Stimuli which caused large changes in vasocon- 
strictor tone in the hands and feet produced little or no change in 
flow in the muscular parts of the limbs (Abr am son, 1944). The infer- 
ence that muscle had a negligible vasoconstrictor innervation 
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