Digoxin antibody decreases natriuresis and diuresis in cerebral hemorrhage.
OBJECTIVE
Brain-damaged patients may develop hyponatremia and natriuresis. Clinical evidence of digoxin antibody effect on natriuresis we found in an 11-year-old boy who developed excessive natriuresis and hyponatremia after brain tumor excision. To better understand the mechanisms involved in these clinical disturbances we used an experimental model of rats subjected to intracerebroventricular (ICV) hemorrhage. The participation of serum ouabainlike activity, possibly a natriuretic compound, and the effects of a specific blocker, digoxin antibody, were studied.


METHODS
The experimental study was performed in four groups of ICV infused Wistar rats: venous autologous blood infused, blood preceded by digoxin antibody, CSF-like solution, and a control group with no cannulation and no infusions. The following parameters were analyzed before and after ICV infusions: weight, urinary volume, and natriuresis. Ouabainlike activity was measured by proportional serum inhibitory activity on normal rat renal medullary Na-K-ATPase activity.


RESULTS
ICV blood but not CSF-like infusion increased urinary volume, natriuresis, and serum ouabainlike activity without weight gain. Natriuresis was positively correlated with serum ouabain activity in ICV blood and blood plus antibody rats. Digoxin antibody restored urinary volume, natriuresis, and ouabainlike activity.


CONCLUSIONS
These data provide evidence of ouabainlike activity involvement in natriuresis and urinary volume changes that occur in cerebral hemorrhage. A possible therapeutic action of digoxin antibody is proposed.
Menezes
João C
JC
Basic Research Laboratory, Nephrology (LIM-12), Medical School, Sao Paulo University, Av. Dr. Arnaldo 455-3° andar-sala 3310 Cerqueira César, CEP 01246 903, São Paulo, Brasil.
Troster
Eduardo J
EJ
Pediatric Intensive Care Unit, Albert Einstein Hospital and Medical School, Sao Paulo University, São Paulo, Brazil.
Dichtchekenian
Varujan
V
Basic Research Laboratory, Nephrology (LIM-12), Medical School, Sao Paulo University, Av. Dr. Arnaldo 455-3° andar-sala 3310 Cerqueira César, CEP 01246 903, São Paulo, Brasil. varujan@uol.com.br.
D000818:Animals; D001921:Brain / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000188:drug therapy*; D002648:Child; D006801:Humans; D007010:Hyponatremia / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000008:administration & dosage / Q000627:therapeutic use*; D007276:Injections, Intraventricular; D008297:Male; D011183:Postoperative Complications; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D007140:Immunoglobulin Fab Fragments; C050199:digoxin antibodies Fab fragments; D000254:Sodium-Potassium-Exchanging ATPase