Effects of Beta-Adrenergic Blockade on Diabetes-Induced Neurobehavioral Alterations in Mice

Neurobehavioral activities were estimated in three groups of male albino mice using the open field, elevated plus maze, light/dark board, and hole-board tests. The control group included intact animals, while alloxan-induced diabetes was evoked in the other two groups (single i.p. injection of 120 mg/kg alloxan). In the third group, a nonspecific beta-adrenoreceptor antagonist, propranolol, was i.p. injected (40 mg/kg) before the induction of diabetes. In diabetic mice, all neurobehavioral indices tested in the four above-mentioned tests were significantly (P< 0.05) smaller than those in the control group. The frequencies of rearings and grooming episodes in the open field, number of entries into the open arms and time spent in these arms in the elevated plus maze test, and number of head dips in the hole-board test demonstrated the most intense drops (more than twofold). Pretreatment with propranolol provided significant (P < 0.05) normalization of all neurobehavioral indices in diabetic mice; such normalization with respect to the locomotion intensity, frequency of grooming, time spent in the open arms, and both indices in the light/dark board was nearly complete. Thus, diabetes in the animal model used is accompanied by the development of the state of abnormally high anxiety. The activity of the betaadrenergic system is noticeably involved in the formation of this state; pharmacological blocking of beta-adrenoreceptors provides significant anxiolytic effects.

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