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HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY I 



angina pectoris, reported by Lindgren & Olivecrona 

 (176), and by White & fiiand (294). 



Electrical stimulation of the central end of the cut 

 great splanchnic nerves produced some of the more 

 painful experiences seen in man by Foerster (77, 

 p. 32). When the patient is under spinal anesthesia 

 pain upon splanchnic stimulation is referred some- 

 where in the chest above the level of analgesia, 

 according to Adson (3) and Leriche (166). On the 

 other hand, in patients in whom we have stimulated 

 the central stump of the greater and lesser splanchnic 

 nerves under local anesthesia the pain has always 

 been referred to the ipsilateral abdomen. Such pain 

 appeared at the same low threshold without delay 

 and was of about the same intensity as that evoked 

 from the twelfth intercostal nerve several centimeters 

 lateral to the rami communicantes (296, p. 83). 

 Such pain also ensued upon stimulation of the twigs 

 of origin of the greater and lesser splanchnic nerves 

 from the sympathetic trunk and from their rostral 

 cut ends. From all of these nerves no sensation oc- 

 curred upon high voltage stimulation of their caudal 

 cut ends. 



Bilateral sympathectomy from the midthoracic 

 through the third lumbar ganglia and including 

 the splanchnic nerves from the T7 ramus to beyond 

 the celiac ganglion (performed for hypertension) 

 yielded a series of patients for study of abdominal 

 visceral sensation by Ray & Neill (221). They found 

 the pain sense absent in these patients in the stomach, 

 intestine (except the rectum), extrahepatic biliary 

 tract, pancreas, kidney and ureter. The stimuli for 

 pain included distension by balloons of hollow viscera, 

 and traction and faradic stimulation of all the 

 structures mentioned. Studies after unilateral sym- 

 pathectomy revealed a homolateral afferent supply 

 for kidney, ureter, the two sides of the colon and pos- 

 siblv the gastric mesentery; the remaining organs 

 had a bilateral supply. Bentley & Smithwick (22) 

 had shown earlier that balloon distension of the duo- 

 denum and jejunum was no longer painful after 

 thoracolumbar sympathectomy and splanchnicec- 

 tomy. Bentley (21) stopped the pain evoked by 

 transfixing an exposed duodenal ulcer with a needle 

 when he procainized the splanchnic nerves. Numer- 

 ous other animal and experimental studies confirm 

 that the pain afTerents from the abdominal viscera 

 travel with the sympathetic nerves, and a substantial 

 number of patients with pain arising in these viscera 

 have been relieved by appropriate sympathectomy 

 according to White & Sweet (296, pp. 652 to 676). 



Gernandt & Zotterman (96) have made a con- 



tribution not readily feasible in man by recording 

 oscilloscopically from the splanchnic nerve and from 

 fine strands of mesenteric nerve in the cat. Slight 

 pressure or touch to the small intestine gave no elec- 

 trical impulses but pinching the gut or the mesentery 

 produced delta fiber impulses conducted at up to 

 20 m per sec. and much slower impulses in 'C fibers 

 conducted at 0.5 to 2 m per sec. These authors con- 

 cluded that intestinal sensibility is similar to that of 

 skin deprived of its fast conducting afferents. 



In the limbs the presence of afferent fibers in the 

 sympathetic supply is less consistently demonstrable 

 by stimulation in man, especially in the lower limb. 

 However Leriche & Fontaine (168), Foerster et al. 

 (79) and Harris (119) all record examples of pain 

 referred to the upper limb upon stimulus to the in- 

 ferior cervical or stellate ganglion. The author has 

 seen one patient in whom electrodes applied to the 

 first and second thoracic ganglia caused immediate 

 pain in the entire ipsilateral arm and in whom this 

 response recurred upon stimulation of the caudal 

 end of the sympathetic trunk after section below the 

 T2 ganglion — evidence that direct afferent fibers 

 were stimulated. Similar evidence for the lower limb 

 has been cited by Foerster et al. (79, p. 154) and by 

 Echlin (71). White & Sweet have never .succeeded 

 in evoking pain in the leg by stimulation of the lumbar 

 sympathetic trunk or rami. But the type of pain 

 known as causalgia which may follow trauma to 

 nerves especially in the limbs is consistently stopped 

 by sympathectomy. This fact is extensively docu- 

 mented in table XIV of White & Sweet (296, p. 369). 

 A possible explanation other than the elimination of 

 direct afferent pathways in the sympathetics has been 

 suggested by Doupe et al. (68), namely that at the 

 site of injury artificial synapses appear permitting 

 tonic efiferent impulses in sympathetic nerves to excite 

 somatic afferents for pain. If this is true the fiber 

 interaction phenomenon of Granit et al. (109) has 

 major clinical significance. Relevant also are experi- 

 ments of Walker & Nulsen (280). They applied a 

 chronic pull-out electrode to the sympathetic chain 

 between the T2 and T3 ganglia and divided the 

 trunk below this electrode in 12 patients. Onh- in the 

 three who had causalgia did any pain appear in the 

 arm and hand on stimulus postoperatively. In the.se 

 three there was a consistent pattern in which the 

 pain appeared only 4 to 20 sec. after the start of 

 stimulus, usually a few seconds after piloerection 

 over the whole upper limb. Maximal pain was not 

 reached for 15 to 30 sec; then, despite continuation 

 of the stimulus, it slowly faded and disappeared 15 



