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

• Published in: Journal of neuroendocrinology Vol. 21; no. 2; pp. 151 - 154
• Main Authors: De Arruda Camargo, G. M. P., De Arruda Camargo, L. A., Saad, W. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2009; Blackwell
• Subjects: Animals; Antidiuretic Hormone Receptor Antagonists; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Male; medial septal area; Microinjections; Protein Isoforms - metabolism; Rats; Receptors, Vasopressin - metabolism; Septal Nuclei - cytology; Septal Nuclei - metabolism; Sodium - urine; sodium excretion; Urination; urine excretion; V1a and V2 receptors; vasopressin; Vertebrates: endocrinology; Urine; Biological fluid; Excretion; Via and V2 receptors; Rat; Septum nucleus; Rodentia; Central nervous system; Neuropeptide; Vasopressin; Encephalon; urine excretion; Vertebrata; Mammalia; medial septal area; Sodium; Animal; Neurohypophyseal hormone; sodium excretion; Subtype; Vasopressin receptor; Biological receptor
• ISSN: 0953-8194; 1365-2826
• DOI: 10.1111/j.1365-2826.2008.01816.x

The present study aimed to determine the effects of selective antagonists of V1a, V2, and V1a/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 V1a antagonist decreased, and the V2 antagonist and Conivaptan (a V1a/V2 antagonist) increased, the urinary flow induced by AVP. Administration of AVP increased sodium excretion. Pretreatment with V2 or V1a antagonists decreased, and Conivaptan abolished, the sodium excretion induced by AVP. These results indicate that the V1a and V2 receptors of the MSA are important in the central regulation of urine and sodium excretion.