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HANDBOOK OF PHYSIOLOGY 



CIRCULATION II 



table 8. Comparative Effects of Epinephrine and Arterenol on Human Renal J 'aseular Dy 



namies 



[After Werko et at. (335)] 



in C In and 40 per cent in RPF; FF increased by 39 

 per cent. Also employing Gomez' calculation, they 

 computed that the greatest resistance increase was in 

 the venular and venous component, and suggested 

 that this contributed significantly to the kidney vol- 

 ume increase that had been noted some time ago 

 from epinephrine, the so-called "paradoxical ex- 

 pansion" of Richards and Plant. The work of Mehrizi 

 and Hamilton (201) in the dog kidney has confirmed 

 this conclusion for arterenol. Note that in the data of 

 Werko et al. (table 8), RAe (efferent arteriolar resist- 

 ance) and RY (venous resistance) increased equally 

 after epinephrine, and the change was most pro- 

 nounced in RAa (afferent arteriolar resistance). 



Studies were made in which measurements of 

 Tm G and Tmp AH were combined in the dog and 

 human (149, 208). In the dog, the ratio GFR Tm G 

 decreased significantly, due to over-all reduction in 

 filtration rate in each glomerulus, rather than nephron 

 shutdown, according to Houck (149). But Mills 

 et al. (208) state that GFR and Tm G decrease together 

 with epinephrine and arterenol, implying nephron 

 closure; this might be anticipated with higher dosage. 

 In the human, the dosage employed (0.243 /ig kg min 

 of epinephrine, 0.321 fig kg min of arterenol) caused 

 no significant alteration of GFR or Tra PAH , although 

 RBF fell to 63 per cent of control. Changes in E PAH 

 were never observed by several groups of workers. 



sympathomimetic drugs. Several sympathomimetic 

 substances have been studied for comparative effects 

 on renal blood flow (5, 1 14, 293). None of a series of 

 rapidly acting vasodepressors, such as isoproterenol 

 and ethylarterenol, injected into the renal artery of 

 dogs (flow measured by electromagnetic flowmeter) 

 induced vasoconstriction (114, 293). Epinephrine, 

 tried in this series, caused the most potent constric- 

 tion. The amylbutyl and isobutylamine derivatives of 

 arterenol, even in quite large doses, were devoid of 

 any renal vasomotor action despite the fact that they 



exhibited definite vasodepressor actions on the sys- 

 temic circulation. It was concluded that the renal 

 circulation does not exhibit sympathetic inhibitory 

 receptors. 



Aviado et al. (5) grouped a number of drugs into 

 four categories, based upon effects observed in the dog 

 kidney by intrarenal arterial or systemic intravenous 

 injection. Direct flow was measured by rotameter. 

 Type A: Drugs which are capable of constricting renal 

 vessels when injected into the renal artery or when 

 given intravenously: levarterenol, epinephrine, phen- 

 vlephrine, metaraminol, methoxamine, and nephazo- 

 line. Type B: Drugs which constrict when injected 

 into the renal artery but, when injected intravenously, 

 constriction is not always encountered : ephedrine, 

 phenylpropanolamine, hydroxyamphetamine, and 

 compound 45-50. Type C: These have no important 

 actions when injected into the artery. When injected 

 intravenously, renal blood flow is increased because 

 of their systemic pressor effect : methamphetamine, 

 pseudoephedrine, amphetamine, pholedrine, methyl- 

 aminoheptane, tuaminoheptane, mephentermine, and 

 phenylpropylmethylamine. Type D: Drugs that have 

 a local dilator action; when they are injected intra- 

 venously, renal blood flow is decreased as a result of 

 arterial depressor action: isoproterenol, nylidrin, 

 isoprophenamine, methoxyphenamine, and cyclo- 

 pentamine. Spencer (293) reported a weak constrictor 

 action by isoproterenol, but this was not encountered 

 in the above series because smaller doses were used. 



A similar analysis of various sympathomimetic 

 drugs on renal hemodynamics has been made recently 

 by Milhetal. (210), employing clearance in normoten- 

 sive and hypotensive drugs. In this series, mephen- 

 termine had the least effect on GFR and RBF, and 

 methoxamine the greatest. 



ganglionic blocking agents. Ganglion-blocking 

 drugs interfere with the reflex adjustments of the 

 circulation. They block the vasoconstrictor pathways 



