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Brains of rats submitted to short‐term alcohol administration retain the ability to respond appropriately to an acute osmotic challenge
Author(s) -
Somponpun Suwit J,
Sato Aileen K,
Uyehara Catherine F T
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a508-d
Subject(s) - vasopressin , diuresis , endocrinology , medicine , alcohol , tonicity , osmotic concentration , ethanol , hypertonic saline , chemistry , kidney , biochemistry
Despite the common notion that diuresis following alcohol exposure persists as a result of suppressed vasopressin (VP) release from the brain, we previously have shown that any suppression of plasma VP (pVP) is transient and its level returns to baseline even when blood alcohol remains significantly elevated. In this study we hypothesized that the persistent diuresis after alcohol dosing is not due to an inability of VP neurons to respond and the peptide released from the brain. Thus, we compared the response of VP neurons to an acute osmotic challenge in adult male Sprague Dawley rats that received either water or ethanol (40% v/v) at 1% BW i.g. for 5 days. On the next day, rats were given an i.v. 5% NaCl ramp at 10μl/100g/min. Blood was sampled every 20 min for determination of a plasma Na ‐ pVP dose response for 80 min, followed by rat brain harvest to determine cFos immunoreactivity in the supraoptic neurons. There was no difference in resting pVP between the two groups of rats. Alcohol rats were able to mount a full VP dose‐response and expressed cFos appropriately to the hypertonic challenge, suggesting that their brains retained the ability to detect and respond to the stimuli. The results do not suggest a suppressed VP secretion from the brain. Rather, the persistent diuresis that accompanies acute alcohol intake reflects primarily a decrease in kidney responsiveness to VP as previously shown. Supported by US Army Medical Command