The Effect of Hypothyroidism on morphine dependence in mice

In this study, physical dependence in male hypothyroid Swiss-Webster mice was investigated by evaluating of morphine withdrawal signs. Animals were divided into four groups: control, morphine dependent, hypothyroid and hypothyroid morphine dependent. Hypothyroidism was induced by administering propylthioracil (PTU) 0.1% for 2 weeks into drinking water of the animals. Animals at control groups only received tap water. Morphine dependency was induced by intraperituneal injection of morphine hydrochloride for 4 days according to Marschall method. Withdrawal signs were evaluated 1 hour after the last administration of morphine by intraperituneal injection of naloxone in experimental groups. The results of the present study showed that morphine dependence was greater in hypothyroid animals compared to control and dependent groups and withdrawal signs were more serious (p < 0.05). These results suggest that hypothyroidism could affect on morphine dependence by possible altering in numbers or affinities of the opioid receptors in the nervous system.