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HANDBOOK OF PHYSIOLOGY 



CIRCULATION II 



DOG 9. 



ISOPROPYL 

 NOREPINEPHRINE 

 J Iy /Kq/min. 

 « 2 » 



40 50 



TIME — MINUTES 



80 



90 



fig. 7. Changes in extracellular Na and K associated with blood pressure changes in the dog. 

 [From Friedman et al. (73).] 



produced its own characteristic pattern. The depres- 

 sor response to acetylcholine, histamine, and isopro- 

 terenol was accompanied by oscillations in the tracing 

 which tended to be inverse to those observed with 

 pressor agents. Later, in a similar arrangement using 

 two electrodes, norepinephrine was shown to produce 

 a rise in (K + ) inverse to the fall in (Na + ) (81 ). 



The technique for electrode monitoring of (Na + ) 

 and (K + ) in flowing blood was then modified after 

 Haddy so as to control flow rate through the electrode 

 as well as through the vasculature of the limb (122). 

 The femoral artery of the dog was interrupted by a 

 length of polyethylene fed through a Sigmamotor 

 pump. The femoral vein was similarly lengthened and 

 passed through a smaller division of the pump. The 

 venous outflow passed through Na and K cannula 

 electrodes in a shielded enclosure. This arrangement 

 ensured not only a constant limb inflow but also the 

 passing of a proportion of the venous outflow at 

 a constant rate past the electrodes. Quantitative 

 measurements could also be made, since calibrating 

 solutions could be injected into the venous tubing 

 proximal to the pump. One pressure transducer was 

 inserted on the arterial side between pump and limb 

 and another into a brachial artery. Small amounts of 



vasoactive agents sufficient only to activate the limb 

 vasculature without producing any noticeable sys- 

 temic effects were used. 



In general, limb vasoconstriction induced by nor- 

 epinephrine or epinephrine was associated with a fall 

 in blood (Na + ) and often with a rise of (K+). Larger 

 doses tended to produce a biphasic response in (Na + ), 

 that is, an initial transient rise preceding the fall. 

 Vasoconstriction produced by serotonin or angioten- 

 sin was associated with similar (Na + ) change unac- 

 companied by any consistent (K + ) deflection. Vaso- 

 constriction produced by Pitressin was associated with 

 a fall in (Na + ) and consistent rise in (K + ), both notice- 

 ably greater in degree and duration than with other 

 agents producing an equal degree of vasoconstriction. 

 Limb vasodilatation induced by isoproterenol, acetyl- 

 choline, or histamine was accompanied by a rise in 

 blood (Na + ) without any consistent change in (K + ). 



A full analysis of rates and relations of ion and water 

 movement is clearly required. For the moment, we 

 mav conclude that the movements of Na and K. 

 associated with changes in blood pressure reflect 

 changes in tension in the peripheral blood vessels. 



Onlv one report disturbs the general consistency 

 of this phase of the investigation. Headings et al. (109) 



