>Sender: >To: >X-Original-Message-ID: <009d01bf3141$7fee6b70$9acf69cf@pacbell.net> >From: "Peter McWilliams" >Subject: Good news on the depression front >Date: Wed, 17 Nov 1999 13:19:57 -0800 >X-Mozilla-Status: 8001 >X-Mozilla-Status2: 00000000 > > >Pubdate: Nov 6, 1999 >Source: New Scientist (UK) >Page: 6 >Copyright: New Scientist, RBI Limited 1999 >Contact: letters@newscientist.com >Website: http://www.newscientist.com/ >Author: (no byline) > >THE MORE THE MERRIER > >PROZAC stimulates the birth of new brain cells in rats, say scientists from >New Jersey. The finding gives clues to what causes depression in people, >how drugs like Prozac relieve it and why the effect takes so long to kick >in. > >Just over a year ago, researchers showed that people grow new neurons all >the time. This overturned a long-held belief that brain cells, unlike cells >in other parts of the body, are not replaced when they die. > >Barry Jacobs and Casimir Fornal at Princeton University put together >findings from several different brain studies. They knew, for instance, >that depressed people have a smaller hippocampus--a structure that is >involved in learning and memorythan healthy people. > >They also knew that chronic stress can slow neuron birth, or neurogenesis, >in the brains of rodents. Stress is thought to contribute to depression. "A >little light went on in my head," says Jacobs. "It just occurred to me that >maybe this is what depression is all about." > >Jacobs and Fornal went on to show that activating one type of receptor for >the neurotransmitter serotonin in rats' brains increased the birth of >neurons. So they decided to see if Prozac, which belongs to a class of >drugs known as selective serotonin re-uptake inhibitors (SSRIs), would have >the same effect. SSRIs prevent serotonin from being mopped up, leaving more >of it around to transmit messages. > >The team gave daily injections of Prozac to five rats for 21 days. Five >control rats were injected with saline. During the final 7 days, they also >gave the rats a chemical called BrdU, which labels new neurons. When they >examined the rats' brains, 69 per cent more new neurons had appeared in the >brains of the Prozac-treated rats compared with the controls. > >Jacobs and Fornal believe that the waxing and waning of neurogenesis in the >hippocampus may be an important factor in explaining why people slump into >depression and why they recover with SSRls. It may also explain why Prozac >takes several weeks to improve mood. "The time needed for these newly >generated cells to mature and make appropriate connections provides an >explanation for the 'therapeutic lag' in antidepressant therapy," Jacobs >told the meeting. > >Jacobs thinks serotonin could also help to treat other neurological >diseases, such as Alzheimer's. But he cautions that it probably won't be of >use to healthy people: "Their level of neurogenesis might already be >optimal." > > > >================================================================ > >This message is sent to you because you are subscribed to > the mailing list . >To unsubscribe, E-mail to: