Medial Septal Area Vasopressin Receptor Subtypes in the Regulation of Urine and Sodium Excretion in Rats

Authors: de Arruda Camargo, G. M. P.; de Arruda Camargo, L. A.; Saad, W. A.

Source: Journal of Neuroendocrinology, Volume 21, Number 2, February 2009 , pp. 151-154(4)

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Abstract:

The present study aimed to determine the effects of selective antagonists of V_1a, V₂, and V_1a/V₂ (Conivaptan; Astellas Pharma Inc., Tokyo, Japan) arginine vasopressin (AVP) receptors on the flow of urine and sodium excretion induced by AVP, by means of microinjections into the medial septal area (MSA) of the rat brain. Male Holtzman rats had a guide cannula implanted into the dorsal surface of the MSA. Intravenous infusion of hypotonic saline was used to promote urinary flow, which was collected for 4 h. Pretreatment with the V_1a antagonist decreased, and the V₂ antagonist and Conivaptan (a V_1a/V₂ antagonist) increased, the urinary flow induced by AVP. Administration of AVP increased sodium excretion. Pretreatment with V₂ or V_1a antagonists decreased, and Conivaptan abolished, the sodium excretion induced by AVP. These results indicate that the V_1a and V₂ receptors of the MSA are important in the central regulation of urine and sodium excretion.

Keywords: vasopressin; medial septal area; V1a and V2 receptors; urine excretion; sodium excretion

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1365-2826.2008.01816.x

Affiliations: 1: Department of Clinical Analysis, São Paulo State University, UNESP, São Paulo, Brazil.

Publication date: 2009-02-01