Cerebro-spinal Fluid Studies in Alcoholics and Violent Offenders

Overexcitement and disinhibition. Dynamic neurotransmitter interactions in alcohol withdrawal

In alcohol withdrawal, abnormalities occur in a number of neurotransmitter systems: there is reduced inhibitory function, and increased activity of excitatory systems. The former, indicated by reduced GABA and alpha-2-adrenoceptor activity, acts in conjunction with, and is exacerbated by, the latter, which itself may be due to the potentiation of NMDA activity by depletion of magnesium, and overactivity of catecholaminergic and CRF neurones. These dysfunctions produce immediate effects and may also contribute to the long-term changes in brain excitability by a kindling-like process. It is possible that early and active treatment may oppose this process. Present strategies for treatment of alcohol withdrawal enhance GABA and alpha-2 inhibitory, or reduce excitatory, mechanisms. Future possibilities include the use of CRF and/or NMDA antagonists.

Neuropharmacological and clinical aspects of alcohol withdrawal

Abnormalities in the function or activity of several neurotransmitter systems have been demonstrated after acute and chronic, exposure to alcohol, and in alcohol withdrawal. The changes can be divided into alterations in function of inhibitory and excitatory systems. Inhibitory dysfunction is indicated by reduced gamma-aminobutyric acid and alpha-2-adrenoceptor activity. In conjunction with, and exacerbating this, is increased activity of excitatory systems, perhaps the most significant of which is the probable potentiation of N-methyl-D-aspartate activity by depletion of magnesium. There is additional, and possibly secondary, overactivity of catecholamine and corticotropin releasing factor neuronal systems. Other, less specific changes include increased numbers of calcium channels, which would increase neuronal excitability. The evidence for these changes is presented, and the implications for new treatment regimes for alcohol withdrawal are discussed.

The neurochemistry of anxiety: an update

1. Recent neurochemical investigations have enhanced our understanding of the anxiety disorders. Emphasis has been placed on dysfunction in central benzodiazepine, serotonergic and noradrenergic systems. 2. Changes in activity of endogenous ligands for the benzodiazepine receptor or in benzodiazepine receptor sensitivity appear to modulate anxiety. 3. There is evidence of serotonergic involvement in anxiety, in that serotonin agonists may increase anxiety, whilst drugs that reduce serotonin function are anxiolytic. 4. Noradrenergic dysfunction, especially that of alpha-2-adrenoceptors, provides the strongest etiological evidence in the development of anxiety. 5. A number of testable hypotheses can be generated from our present knowledge. As a result, new and more specific treatments may become apparent for the anxiety disorders.