Clonidine, a potent antihypertensive drug, has other pharmacological effects, including-analgesia, reduction of opiate withdrawal intensity, anxiolytic effect, and so on.
In this paper, the influence of clonidine on the morphine-induced increase of plasma corticosterone level was investigated in male mice.
The obtained results were summarized as follows;
1. The tolerance to the morphine-induced increase of plasma corticosterone level was rapidly developed within one week, and the development of tolerance was not affected by clonidine.
2. Acute administration of clonidine did not significantly change the normal plasma corticosterone level, but the morphine-induced increase of plasma corticosterone level was markedly suppressed by the pretreatment of clonidine.
3. The plasma corticosterone level at 10 hours after the cessation of the long-term (7 days) medication of morphine, clonidine or clonidine plus morphine was, respectively, much lower than that of the control group.
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