MORE ON SEROTONIN SYSTEM

The serotonin system is thought to regulate most, if not all, complex
behaviours, but it has been hard for researchers to get a handle on the
system which involves at least 14 distinct types of serotonin receptors.
This week, US scientists report that genetically engineered mice lacking
the 5-HT1A inhibitory serotonin receptor are more anxious than their normal
littermates and that they behave like mice that have been given
antidepressants.

"Our speculation", says senior author, Laurence Tecott (University of
California, San Francisco, CA, USA) "is that both these
abnormalities--anxiety and antidepressive responses--can be accounted for
by disinhibition of serotonin system activity". The mutant mice "have
potential as a model for investigating mechanisms through which
serotonergic systems modulate affective state and mediate the actions of
psychiatric drugs", conclude the authors (Proc Natl Acad Sci USA 1998; 95:
15049-54).

Checked-by: Pat Dolan