Cortical beta-adrenergic subsensitivity after desmethylimipramine may depend on the passage of time rather than daily treatment.

Earlier data from our laboratory indicated that the effects of antidepressants on dopamine autoreceptors are dependent on the passage of time rather than repeated treatment. The present study inquired whether the same might be true of cortical beta-adrenergic receptors. Our findings indicate that beta-adrenergic subsensitivity is obtained whether rats were treated with desmethylimipramine daily for 17 days or only on day 1 and day 17. These data suggest that antidepressant-induced changes in beta-receptor sensitivity may, like those in dopamine autoreceptors, also depend on the passage of time.