Injection of rats with morphine or methadone, before they received a water load equivalent to 5% of their body weight, produced a dose‐dependent antidiuretic effect. Following the antidiuresis, urine was eliminated with kinetics similar to control untreated rats.
The antidiuretic effect of morphine or methadone was blocked by naloxone administered before the opiate, or reversed when given after the opiate.
Rats implanted with morphine pellets developed a marked degree of tolerance to the antidiuretic effect of morphine. Tolerance was also obtained on injection of three daily doses of morphine or methadone over two days.
Withdrawal symptoms were precipitated by naloxone in rats implanted with pellets of morphine; under these conditions the animals showed a marked reduction in urine production as compared to naive rats.
Injection of rats with morphine or methadone, before they received a water load equivalent to 5% of their body weight, produced a dose‐dependent antidiuretic effect. Following the antidiuresis, urine was eliminated with kinetics similar to control untreated rats.
The antidiuretic effect of morphine or methadone was blocked by naloxone administered before the opiate, or reversed when given after the opiate.
Rats implanted with morphine pellets developed a marked degree of tolerance to the antidiuretic effect of morphine. Tolerance was also obtained on injection of three daily doses of morphine or methadone over two days.
Withdrawal symptoms were precipitated by naloxone in rats implanted with pellets of morphine; under these conditions the animals showed a marked reduction in urine production as compared to naive rats.
DOI: 10.1111/j.1476-5381.1978.tb17286.x
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