Related Experiment Video

Updated: Aug 19, 2026

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
10:26

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology

Published on: August 18, 2014

Urinary responses to acute moxonidine are inhibited by natriuretic peptide receptor antagonist

Rouwayda El-Ayoubi1, Ahmed Menaouar, Jolanta Gutkowska

  • 1Laboratory of Cardiovascular Biochemistry, Centre hospitalier de l'Université de Montréal-Hotel-Dieu, and Department of Medicine, Université de Montréal, Montreal (Quebec), Canada.

British Journal of Pharmacology
|February 9, 2005
PubMed

Insights

Moxonidine and clonidine stimulate the release of atrial natriuretic peptide (ANP), a hormone that promotes urination and sodium excretion. These effects are mediated by ANP acting on renal receptors, with some differences observed in hypertensive rats.

Area of Science:

  • Pharmacology
  • Nephrology
  • Cardiovascular Physiology

Background:

  • Previous studies indicated that moxonidine and clonidine increase plasma atrial natriuretic peptide (ANP).
  • ANP is a hormone known for its vasodilator, diuretic, and natriuretic properties.
  • Hypertension may alter the renal response to ANP-mediated effects.

Purpose of the Study:

  • To investigate if moxonidine stimulates ANP release.
  • To determine if ANP mediates diuresis and natriuresis induced by moxonidine.
  • To examine potential alterations in these effects in the context of hypertension.

Main Methods:

  • Intravenous administration of moxonidine and clonidine to normotensive (Sprague-Dawley, Wistar-Kyoto) and spontaneously hypertensive rats (SHR).
  • Dose-dependent assessment of diuresis, natriuresis, kaliuresis, and cGMP excretion.
  • Pharmacological blockade using yohimbine (alpha2-adrenoceptor antagonist) and efaroxan (imidazoline I1-receptor antagonist).
  • Administration of anantin (natriuretic peptide antagonist) to evaluate ANP's role.
  • Measurement of plasma ANP levels.

Main Results:

  • Moxonidine and clonidine dose-dependently stimulated diuresis, natriuresis, kaliuresis, and cGMP excretion, effects more pronounced in the first hour.
  • The actions of clonidine and moxonidine were inhibited by yohimbine and efaroxan.
  • Moxonidine-stimulated urine output and electrolyte excretion were lower in SHR compared to normotensive rats, suggesting strain-specific influences.
  • Anantin significantly inhibited moxonidine-induced urinary effects.
  • Moxonidine administration led to a significant increase in plasma ANP levels across all rat strains.

Conclusions:

  • Natriuretic peptides are confirmed to mediate the urinary actions of moxonidine.
  • These effects are mediated through natriuretic peptide receptors.
  • While hypertension (SHR) showed some altered responses, the primary mechanism involves ANP, indicating strain-specific, rather than pressure-specific, influences on these pathways.

More Related Videos

The Use of Cystometry in Small Rodents: A Study of Bladder Chemosensation08:08

The Use of Cystometry in Small Rodents: A Study of Bladder Chemosensation

Published on: August 21, 2012

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Small Rodents07:42

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Small Rodents

Published on: April 25, 2017

Related Concept Videos

Antihypertensive Drugs: Vasodilators01:23

Antihypertensive Drugs: Vasodilators

Vasodilators, primarily affecting the smooth muscles within arterial and venous walls, are commonly used for hypertension treatment. Medications such as minoxidil and hydralazine primarily target arteries and arterioles, while sodium nitroprusside acts on arterioles and venules. Minoxidil, functioning as a prodrug, is metabolized by hepatic sulfotransferase into its active form, minoxidil sulfate, after oral administration. This metabolite binds to the sulfonylurea receptor (SUR) component of...
Cholinergic Antagonists: Pharmacological Actions01:28

Cholinergic Antagonists: Pharmacological Actions

Antimuscarinic drugs block muscarinic receptors in multiple systems, including the gut, eye, smooth muscles, respiratory tract, cardiovascular, and central nervous systems. They produce similar effects with varying selectivity depending on the specific agent and tissue. Here are the key pharmacological actions of antimuscarinics:
Gastrointestinal Effects: Antimuscarinics reduce gut contractions, increase gastric emptying, and slow intestinal transit. They partly inhibit gastric acid secretion...
Cholinergic Antagonists: Pharmacokinetics01:24

Cholinergic Antagonists: Pharmacokinetics

Cholinergic antagonists—such as antimuscarinics—are available in oral, topical, ocular, parenteral, and inhalational formulations. Most antimuscarinics are oral formulations,  while scopolamine is available as a topical patch, and ipratropium and tiotropium are available as inhalation aerosols or powders. Atropine, tropicamide, and cyclopentolate are topically instilled in the eye. Most antimuscarinics are lipid-soluble and readily absorbed from the gastrointestinal tract and the conjunctiva.
Antihypertensive Drugs: Thiazide-Class Diuretics01:15

Antihypertensive Drugs: Thiazide-Class Diuretics

Thiazide diuretics are sulfonamide derivatives featuring a benzothiadiazine ring system in their molecular structure. Based on this structure, thiazide diuretics can be categorized into two groups: thiazide-type and thiazide-like diuretics. Thiazide-type diuretics, including hydrochlorothiazide and chlorothiazide, consist of a benzothiadiazine backbone with an attached sulfonamide group. Thiazide-like diuretics, such as chlorthalidone and indapamide, lack the thiazide ring but demonstrate...
Antihypertensive Drugs: Potassium-Sparing Diuretics01:28

Antihypertensive Drugs: Potassium-Sparing Diuretics

Liddle syndrome is a genetically inherited form of hypertension characterized by the overactivity of epithelial sodium channels in the nephron, the functional unit of the kidney. This heightened activity leads to increased sodium reabsorption and excessive excretion of potassium. To counteract this, potassium-sparing diuretics such as amiloride are used. They function by blocking these sodium channels, thereby reducing the influx of sodium into the epithelial cells and minimizing the loss of...
Direct-Acting Cholinergic Agonists: Pharmacological Actions00:59

Direct-Acting Cholinergic Agonists: Pharmacological Actions

Direct-acting cholinergic agonists exert their pharmacological actions by mimicking the effects of acetylcholine on postsynaptic muscarinic receptors to generate parasympathetic responses. These agents elicit a range of physiological responses, including cardiovascular effects. For example, activation of muscarinic receptors induces bradycardia, decreased cardiac output, reduced peripheral resistance, and consequent hypotension. In the eye, stimulation of M3 receptors leads to smooth muscle...