Browsing by Author "CROXATTO, R"

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    EFFECT OF MORPHINE ON THE CLEARANCE OF ENDOGENOUS CREATININE AND BLOOD CLINICAL CHEMICALS IN THE RAT
    (1979) HUIDOBRO, F; CROXATTO, R; HUIDOBROTORO, JP
    The effect of morphine on urine and blood serum concentration of Na+, K+, Cl- and other chemicals was determined using Sprague Dawley rats, previously hydrated with 50 ml/kg of 0.5% NaCl to provoke an increased diuresis. Morphine caused about a 90% decrease in the urine concentration of Na+, K+ and Cl-. This reduction in the urine electrolyte excretion was associated with a small but significant increase in the concentration of the blood Na+ and Cl-. The anti-diuresis and the decrease in urine electrolytes caused by morphine was paralleled by a 50% reduction of the endogenous creatinine clearance. An acute dose of 7.5 mg/kg morphine i.p. did not alter the concentration of 13 other clinical blood chemicals with the exception of urea. After 18 h of morphine pellet implantation, a significant increase was found in the blood urea and in the activity of serum transaminases. Lactic dehydrogenases isoenzymes 1 and 2 were significantly increased in the blood of rats chronically administered with morphine.
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    EFFECTS OF BETA-ENDORPHIN AND D-ALANINE2 ENKEPHALINAMIDE ON URINE PRODUCTION AND URINARY ELECTROLYTES IN THE RAT
    (1979) HUIDOBROTORO, JP; HUIDOBRO, F; CROXATTO, R
    The intracerebro-ventricular administration of human .beta.-Endorphin (.beta.-EP, 0.1-3 .mu.g/rat) or D-alanine2 methionine enkephalinamide (D-ala, 0.3-30 .mu.g/rat) caused a dose dependent reduction in urine volume. The oliguria was associated with a decrease in the concentration of Na+ and K+ in the urine of rats previously hydrated by oral administration with 25 ml/kg tap water plus 50 ml/kg 0.5% NaCl. On a molar basis, .beta.-EP proved to be about 5-7 times more potent than D-ala. The effects caused by the peptides were antagonized by simultaneous i.p. administration of 1 mg/kg naloxone. In rats treated chronically with morphine, no cross-tolerance was demonstrated to the antidiuretic effect of .beta.-EP, but clear cross-tolerance was evident to the changes in urine electrolytes induced by .beta.-EP. Morphine and the opiate peptides may share a similar mechanism of action.