Indexed on: 01 Dec '85Published on: 01 Dec '85Published in: Psychopharmacology
Eight normal volunteers had IV infusions of 200 μg clonidine (a centrally-acting adrenergic agonist which reduces noradrenaline release), and saline in a “double-blind” cross-over design. Clonidine reduced subjective estimates of arousal but did not affect performance on the Digit Symbol Substitution Test. Clonidine impaired pairedassociate learning, but it did not affect performance on a number of measures of short and long term memory. The findings suggest either 1) that there is a specific (adrenergic) mechanism involved in the acquisition of novel associations, but not in other types of learning, or 2) that paired associate learning is more vulnerable than other learning tasks to disruption of adrenergic transmission.