Medial septal area ANG II receptor subtypes in the regulation of urine and sodium excretion induced by vasopressin.
BACKGROUND
The present study was designed to determine the effects of selective antagonists of angiotensin II receptor types AT(1) and AT(2) on the flow of urine and sodium excretion induced by arginine vasopressin (AVP).


METHODS
To this end, the drugs were microinjected into the medial septal area (MSA) of the brains of male Holtzman rats. Intravenous infusion of hypotonic saline was used to promote urinary flow, which was collected for one hour.


RESULTS
MSA microinjections of AVP decreased the urinary flow and increased sodium excretion in a dose-dependent manner. Microinjection into MSA of an AT(2) antagonist (PD-123319) had a significantly greater effect than with an AT(1) antagonist (losartan) in increasing urinary flow and decreasing sodium excretion. These effects were more pronounced when both antagonists were injected together, before the AVP.


CONCLUSIONS
These results indicate that MSA AT(1) and AT(2) receptors act synergistically in the regulation of urine and sodium excretion induced by AVP.
Pavan de Arruda Camargo
Gabriela Maria
GM
Department of Clinical Analysis, São Paulo State University (UNESP) at Araraquara (SP), Brazil. gabriela.camargo@gmail.com
de Arruda Camargo
Luiz Antônio
LA
Abrão Saad
Wilson
W
D000818:Animals; D008297:Male; D008845:Microinjections; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism*; D020665:Septum of Brain / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D012964:Sodium / Q000652:urine*; D014554:Urination / Q000187:drug effects; D014667:Vasopressins / Q000494:pharmacology*
D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D014667:Vasopressins; D012964:Sodium