Serotonin and its place in the pathogenesis of depression.

The authors review the literature in an attempt to evaluate the relationship between serotonin and depression. Animal studies show that the administration of tryptophan (the precursor of serotonin) increased serotonin synthesis and influenced behavior. Low plasma tryptophan levels have been found in patients with endogeneous depression. Postmortem studies have shown an association between lowered hindbrain serotonin levels and suicide among depressed persons. The decreased serotonin levels in blood platelets during depression mirrored the neuronal changes. Tricyclic antidepressants inhibited platelet serotonin uptake and reduced imipramine binding sites on the platelets. A positive correlation between depression rating scores and platelet aggregatory response has been reported. Serotonin stimulated release of prolactin and growth hormone, although the prolactin response was less marked in depression. A marker for depressive illness is still sought, but it is likely to be related in some way to serotonin.

Clinical and pharmacological effects of treatment with a new antidepressant.

The novel tetracyclic piperazino-azepine compound Org GB 94 (Tolvon, Tolvin) in a dose of 20 mg three times daily was found to be of save markedly and significantly less side-effects. Patients with reactive depression and those with endogenous depression reponded equally well to Org GB 94. No correlation was found between plasma levels of Org GB 94 and either clinical effects or side-effects. Org GB 94 did not alter the tyramine pressor response, in contrast to amitriptyline.

Beta blockade in lithium tremor.

Practolol, propranolol, and placebo have been tested on an objective test of lithium induced tremor. Both beta-blocking agents produced significantly more tremor than the placebo. It is argued that lithium induced tremor is closer to essential than to physiological tremor.