Postnatal MSG treatment attenuates angiotensin II (AII) induced drinking in rats.
Exogenous angiotensin II (AII) administration produces a robust drinking response, even in water-satiated rats. All receptors are located in the hypothalamus and circumventricular organs (CVOs). Early postnatal administration of monosodium glutamate (MSG) produces hypothalamic/CVO damage. Therefore MSG might damage hypothalamic/CVO neurons important for producing the drinking response to AII. Few noninvasive procedures or tests exist to indicate the presence of a MSG lesion. Thus, the present study sought to determine whether altered water consumption after AII administration would signify the presence of a MSG lesion, as well as to demonstrate hypothalamic/CVO involvement in AII-induced drinking. Adult rats (dosed as neonates with MSG or saline) were given various doses of AII and the beta-adrenergic agonist isoproterenol. MSG-treated rats drank significantly less water after 100 ug/kg, sc AII than control rats. MSG-treated rats also had an unexpectedly high mortality after 100 ug/kg, sc isoproterenol. Thus, measurement of the drinking response may be a sensitive, noninvasive method for detecting neurotoxic damage to hypothalamic/CVO sites critical for the central action of AII.
Caputo
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FDA/National Center for Toxicological Research, Division of Neurotoxicology, Jefferson, AR 72079, USA.
Scallet
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AC
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001786:Blood Glucose / Q000378:metabolism; D001931:Brain Mapping; D002552:Cerebral Ventricles / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects*; D004435:Eating / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009410:Nerve Degeneration / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012970:Sodium Glutamate / Q000494:pharmacology*; D001615:beta-Endorphin / Q000378:metabolism
D001786:Blood Glucose; D000804:Angiotensin II; D001615:beta-Endorphin; D007545:Isoproterenol; D012970:Sodium Glutamate