Abstract
The effects of microinjection of purinoceptor agonists into the hypothalamic supraoptic nucleus (SON) on urination were examined in water-loaded and ethanol-anesthetized rats. Adenosine triphosphate (ATP), but neither adenosine diphosphate (ADP), adenosine monophosphate (AMP) nor adenosine, concentration-dependently decreased the urine outflow with concomitant increase in the urine osmotic pressure. The ED50 value for ATP was approx. 60 nmol. The antidiuretic effect of ATP was blocked either by prior injection of theophylline (an antagonist of the P1-type purinoceptor) or by intravenous administration d(CH2)5-D-Tyr(Et)-valine-arginine-vasopressin (VAVP). These results suggest that ATP injected into the SON has antidiuretic effects due to release of AVP through an activation of theophylline-sensitive purinoceptors.
MeSH terms
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Adenosine Triphosphate / administration & dosage
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Adenosine Triphosphate / pharmacology*
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Anesthesia*
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Animals
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Antidiuretic Hormone Receptor Antagonists
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Arginine Vasopressin / antagonists & inhibitors
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Blood Pressure / drug effects
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Body Temperature / drug effects
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Diuresis / drug effects*
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Ethanol*
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Heart Rate / drug effects
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Male
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Microinjections
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Osmolar Concentration
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Purinergic Agonists
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Purinergic Antagonists
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Rats
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Rats, Wistar
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Receptors, Muscarinic / drug effects
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Receptors, Vasopressin / drug effects
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Respiratory Mechanics / drug effects
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Supraoptic Nucleus / anatomy & histology
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Supraoptic Nucleus / physiology*
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Urodynamics / drug effects
Substances
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Antidiuretic Hormone Receptor Antagonists
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Purinergic Agonists
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Purinergic Antagonists
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Receptors, Muscarinic
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Receptors, Vasopressin
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Arginine Vasopressin
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Ethanol
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Adenosine Triphosphate