The effects of sub-anaesthetic doses of ketamine on memory, cognitive performance and subjective experience in healthy volunteers.

The cognitive and subjective effects of sub-anaesthetic doses of ketamine on healthy volunteers were examined. Twelve healthy volunteers received 25 mg ketamine, 10 mg ketamine and saline placebo, i.m. in a double-blind, Latin square design. A cognitive, perceptual and self-report test battery was administered over 45 min. The order of tests was rotated to control for timing effects. Ketamine (25 mg) significantly affected verbal learning and memory, parallel visual search, some measures of psychomotor performance, measures of arousal, subjective mood ratings and visual perception. Measures of attention and frontal lobe functioning were relatively unaffected. Thus, low doses of ketamine had selective, dose-related effects on memory, perceptual and psychomotor functions. The disruption of memory and perceptual processes may help to explain the unique subjective state induced by ketamine.

Platelet [3H]imipramine and alpha 2-adrenoceptor binding in normal subjects during desipramine administration and withdrawal.

The effect of desipramine 150 mg daily on platelet [3H]imipramine and alpha 2-adrenoceptor binding sites was studied over a 6-week period and for 6 weeks after withdrawal. Modest (10%) increases in [3H]imipramine binding site densities during treatment were noted with a decrease between 1 and 4 weeks after withdrawal. No effect was found on alpha 2-adrenoceptors. Time of day appeared to have some effect on the results found. None of the [3H]imipramine binding site effects of desipramine, on treatment or following withdrawal, was comparable in magnitude to trait differences that were also found between subjects.

The psychopharmacological era: notes toward a history.

Cultural and economic influences on the psychopharmacological era are reviewed, in an attempt to bring into focus what has been happening in psychopharmacology for the past thirty years. It is argued that the belief that clinical advances are made through the heroic achievements of disinterested scientists is a simplistic view that may militate against future significant discoveries. Such discoveries, it is argued, still come about for the most part serendipitously, despite a widespread belief that psychopharmacology has become a rational science.

Centrifugal and anticoagulant induced variations in platelet rich plasma and their influence on platelet aggregation.

Variations in the centrifugal force (g) used to prepare platelet-rich-plasma (PRP) alter not only the number of platelets therein but also their size and reactivity. Anticoagulants also affect these parameters. According we suggest that PRP preparations need to be strictly standardised. Critical comment on the use of the platelet aggregation model as a means of assessing 5-hydroxytryptamine receptor function is included.