Peptidase Inhibitor-Induced Antidiuresis Mediated through Angiotensin and Opioid Receptors in the Rat Hypothalamus

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Author(s)

    • MORI Mayumi
    • Department of Pharmacology, Nagoya City University Medical School

Abstract

We examined the effects on urine outflow rate after microinjections of thiorphan (a carboxypeptidase inhibitor) and bestatin (an aminopeptidase inhibitor) into the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei of anesthetized hydrated rats to determine the possible role of neuropeptides in the regulation of urine production. After individual microinjection of the peptidase inhibitors into the nuclei, only thiorphan at 100 nmol administered into the PVN significantly decreased the urine outflow rate. Two consecutive microinjections of the peptidase inhibitors at 100 nmol each into the nuclei induced potent antidiuresis. These effects after microinjections of the peptidase inhibitors into the PVN and SON were diminished by pretreatment with [Sar<SUP>1</SUP>, Ile<SUP>8</SUP>]angiotensin (ANG) II (an ANG II receptor antagonist) and naloxone (an opioid receptor antagonist) in the PVN and with [Sar<SUP>1</SUP>, Ile<SUP>8</SUP>]ANG II in the SON, respectively. A vasopressin (AVP) receptor antagonist, <I>d</I>(CH<SUB>2</SUB>)<SUB>5</SUB>-<SUB>D</SUB>-Tyr(Et)VAVP (i.v.), completely blocked the antidiuresis by microinjections of the peptidase inhibitors into both the nuclei. Urinary osmotic pressure was significantly increased by consecutive microinjections of the peptidase inhibitors into the PVN and SON. These results suggest that endogenously-released ANG II and opioid peptides in the PVN and ANG II in the SON regulate urine production mediated through increased AVP release.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 71(1), 61-71, 1996-05

    The Japanese Pharmacological Society

References:  46

Codes

  • NII Article ID (NAID)
    10008188320
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00215198
  • Data Source
    CJP  CJPref  J-STAGE 
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