ABSTRACT
Although it is essentially impossible to cover adequately the topic on Basic mechanisms of drug action in Attention Deficit Disorder and Hyperkinetic Syndrome, the three chapters offer a formidable coverage from a neuropharmacological perspective of the problem under consideration. James McGaugh introduced the central theme of memory enhancement (for details, see McGaugh, Introini-Collison, Nagahara, & Cahill, 1988). The choice of this problem was indeed fortunate since the contribution by Normile, Altman and Gershon (this volume) is built upon the ‘global’ strategy of evolving ‘cognition enhancers’ with potential efficacy for a range of cognitive dysfunctions, including ADHD and dementia of the Alzheimer’s type. Trevor Robbins, G.H. Jones, and Barbara Sahakian discuss the possible ‘paradoxical’ effects of the psychomotor stimulants, methylphenidate and d-amphetamine, upon ADHD children in order to develop an understanding of the neuropharmacological mechanisms of these drugs in behavioral procedures. The mediatory effects of the mesolimbic dopamine (DA) projections to the nucleus accumbens and associated structures of the ventral striatum are delineated in the context of the several behaviors stimulated by d-amphetamine. These behaviors and their interactions with the stimulants and the neuroanatomical sites are defined with a careful pursuance of their mechanistic action. This chapter also discussed indications that the hyperactivity and the attention disorder may arise from functional changes in relatively independent catecholaminergic systems and describes the neurobehavioral effects of rearing. Lewis Seiden’s chapter provides a comprehensive review of the successful application of the neonatal 6-hydroxydopamine (6-OHDA) intracerebroventricular procedure, which produces a very drastic, but selective, DA depletion in forebrain areas, to analyse the functional changes produced by extreme hyperactive juvenile and adult rats. Seiden indicates most succinctly the actions of the stimulant drugs on the hyperactivity and performance deficits of neonatally DA depleted rats.
