Prevention by vagotomy or atropine administration of the hemodynamic changes occurring after acute unilateral nephrectomy in the dog.

Publisher Website
Google Scholar
Abstract
Acute unilateral nephrectomy (AUN) increases electrolyte excretion by the remaining kidney and is associated with a decrease in cardiac output (CO). Anesthetized dogs were studied to determine the role of the vagus nerves in these responses to AUN. In 6 intact animals, AUN increased Na excretion (UNaV) from 31.7 .+-. 13.9 to 47.5 .+-. 14.3 .mu.eq/min (P < 0.05) and K excretion (UKV) from 29.3 .+-. 5.2 to 62.0 .+-. 11.4 .mu.eq/min (P < 0.02) as CO fell from 2.8 .+-. 0.2 to 1.9 to 0.3 l/min (P < 0.005) and blood pressure and total peripheral resistance increased; no change in glomerular filtration rate (GFR) occurred but renal blood flow fell significantly. In 7 dogs undergoing sham nephrectomy no significant changes in any variable occurred. In 12 dogs with bilateral cervical vagotomy AUN increased UNaV from 19.3 .+-. 5.3 to 39.6 .+-. 13.7 .mu.eq/min (P < 0.05) and UKV from 35.7 .+-. 5.5 to 46.8 .+-. 5.8 .mu.eq/min, (P < 0.001) without changes in GFR, renal blood flow or mean arterial pressure; CO and total peripheral resistance did not change in this group. In 9 dogs given i.v. atropine sulfate (0.067 mg/kg), AUN resulted in comparable increases in cation excretion but no significant change in CO occurred. The increased electrolyte excretion seen after AUN is not prevented by bilateral cervical vagotomy or by atropine administration. The decrease in CO associated with AUN does not occur under these circumstances; reflex vagal efferent activity is responsible for this hemodynamic change. The increase in electrolyte excretion after AUN can be dissociated from the decrease in CO.