Sympathetic Control of the Peripheral Circulation in Man

Duff, Robert Stewart (1952) Sympathetic Control of the Peripheral Circulation in Man. MD thesis, University of Glasgow.

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Part I: 1. Using a specially constructed plethysmograph the blood flow in the hands and forearms of patients was studied before and after sympathectomy. 2. After sympathectomy there was an immediate threefold increase in forearm blood flow lasting for three or four days in six hyperhidrotic and eight Raynaud limbs. 3. In the bands the blood flow took 24 to 48 hours longer to reach a peak, but the increase was greater, especially in the hyperhidrotic hands, and lasted longer. 4. Preganglionic section was found to cause as much increase in blood flow as ganglionectomy. Part II: 1. The effects of intra-arterial infusions of graded levels of adrenaline on blood flow in the hands of patients before and after sympathectomy, and in the hands of healthy subjects, were measured by plethysmography. 2. An analytical technique was evolved to assess small changes in sensitivity to adrenaline and the range of response of the hands to a series of concentrations of adrenaline was determined. 3. The sensitivity of the hands of patients with Raynaud's disease before sympathectomy was found to be within normal limits. 4. In a group of ten hands tested before and after sympathectomy the mean vasoconstriction with adrenaline was found to increase fourfold after operation, as a result of lowering of the threshold to adrenaline in six of the hands. 5. The concentration of adrenaline required to produce an equal amount of vasoconstriction was four times as much in normal as in sympathectomized hands. 6. Five of the six hands which exhibited a distinct increase in sensitivity had been sympathectomized by preganglionic section. Two of the four hands in which no increase was demonstrated were sympathectomized by ganglionectomy. 7. A further six hands of patients previously sympathectomized for hyperhidrosis or Raynaud's disease were studied at various intervals after operation. Two had significant increases in sensitivity after ganglionectomy and one after preganglionic section. No significant increase was demonstrated in two hands after ganglionectomy nor in one after preganglionic section. 8. Altogether, by the criteria adopted, supersensitivity was present in nine hands, following preganglionic section (6), ganglionectomy (2) and traumatic sympatheotony (1); and absent in seven hands, following ganglionectomy (4) and preganglionic section (3). 9. The evidence was considered to indicate that preganglionic section is no less liable than ganglionectoray to cause supersensitivity of the skin vessels to adrenaline. 10. Supersensitivity was found in tests as early as the sixth day and as late as the 24th month after sympathectomy. Part III: 1. The normal blood flow response in the forearm and calf to 10 minute intravenous infusions of 10 ug. adrenaline per minute was found to consist of an initial marked (four or fivefold) but brief increase followed by a moderate (twofold) but sustained elevation in blood flow. 2. Some evidence that the initial phase is increased after sympathectomy was presented. 3. In sympathectomized forearms the second phase of increased blood flow was shown to be absent and in sympathectomized calves there was found to be, instead, an actual reduction of flow. 4. Intra-arterial infusions of proportionately reduced amounts of adrenaline given to normal subjects produced only a brief initial increase in blood flow in the forearm and calf; during the remainder of the infusions the blood flow was either at the resting level or lower. These effects were considered to be due to the local direct action of adrenaline on vessels in skeletal muscle. 5. The findings thus showed that sympathectomy causes an augmentation of both the initial dilator and the subsequent constrictor phases of the direct action of adrenaline on the muscle vessels. Part IV: 1. All three experimental approaches give consistent evidence that the degree of super sensitivity of the vessels in skin and skeletal muscle resulting from preganglionic section is no less than that following ganglionectomy, in direct contradiction of 'the general law of denervation' of Cannon et al. (1945). 2. The literature concerning the changes following sympathectomy and the circulatory effects of adrenaline is briefly surveyed and certain current views critically reviewed. 3. A hypothesis is put forward to account for the salient changes after sympathectomy in terms of a circulatory redistribution within sympathectoraized tissues causing a higher proportion of blood to flow through specially responsive channels.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: Medicine, Physiology
Date of Award: 1952
Depositing User: Enlighten Team
Unique ID: glathesis:1952-78894
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 14:43
Last Modified: 30 Jan 2020 14:43

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